· The 'BEST' Computer for the Best Educational System in the World! A Superb IBM Compatible...

$3.25MM70924

January 1985

Canada's Magazine for Electronics Et Computing Enthusiasts

Reviews'ECS6 Portable 6502 ACNAP Circuit Design Software Tech Sketch Light Pen EMP 1200A Modem

RS232 Breakout Project

Analog Capacitance Meter Project

0

57438 70924Cosmic Printer/Plotter

Affordable Graphics

The 'BEST' Computer for the Best EducationalSystem in the World!A Superb IBM Compatible Microcomputer

L.anaciian maue grsrareu

Schools and TeacherSpecial Price

anau

$1450Don't be put off by this extra-ordinary price. Check thespecifications and ourwarranty to support them.

See the ReviewIn March 1984

Computing Now!This price includes: 64K of RAM with

presocketed provi-sion for 256K One disk drive.SA455. Double Sid-ed. Double Density

Colour Video Board Floppy controller

capable of handl-ing up to four DSDD51/4" disk drives andsocketed for op-tional serial portand real time clock

Monitor not includ-ed.

64K RAM upgradekits for extramemory . . . 557.00

Full 300 daywarranty

This system includesPhoenix SoftwareBIOS

OR The Loaded "BEST"Everything in our $1450 System plus: Two DS. DD 51/4" Disk Drives On -board 256K of RAM RS232 Port $1895

OR 10 Meg Hard Disk VersionEverything in our $1450 System plus: 10 Meg Hard Disk Drive &

Controller On -board 256K of RAM RS232 Port $2995

The BEST is a compatible microcomputer featuring the following: 8088 processor running at 4.77 MHz for fast service. (Room for the op-tional new co -processors, the most popular being the 8087 "number crunching" processor)

64K RAM expandable up to 256K in blocks of 64K and with the new high density RAMs, there is enough room onboard to hold 1 Megabyte ofdata in blocks of 256K.5 expansion slots each being identical, so the user can upgrade his machine with IBM compatible hardware.D.M.A. controller. Three of the DMA channels are available to the user.A timer/counter. This is used by the system for time of day clock; tone generation of the speaker; and a time base.An 8 level interrupt controller, 6 of which are bussed to the expansion slots for feature cards. The other two are used for the time of day clock,and the keyboard circuits. (There is also a NMI which is not user accessable since it is used for parity checks)Three ROM sockets are available to the user, one generally holds the system BIOS, and the other two can hold any firmware the user wishesto implement.A speaker with 1/2 W of driving power is available to user software which can also control the frequency of oscillation. In fact 3 methods existto modulate the speakers output: 1) direct control or the output bit stream. 2) output from the programmable timer. 3) the timer clock can bemodulated with a program controlled I/O register bit.A keyboard interface which is compatible with all IBM compatible keyboards through a 5 pin DIN connector.

EXCELTRONIXExceltronix Computer Division Computers at unbeatableprices! (416) 921-8941, 3/9 Colleae St., Toronto, Ontario

No returns or exchanges after 7 days 15', restock.ng charge m5T 152Prices may change without notification

Telex 065-24218 1-800-268-3798 - Order line only

Ckde No. 20 on Reader Service Card

EXCELTRONIX To help you celebrate, we also pass the following

We Wish You A Merry Christmas WHOLESALE PRICES TO YOU!

and Happy New Year!We guarantee you the combination of BEST Prices & Service in Canada!

Star Micronics1 year warrantyCSA ApprovedGemini 10X 120 c.p.s., 1000/0 duty cycle 816characters print buffer, option 4K or 8K standard parallel optional RS232C tractor & friction feed.

5379.00

Gemini 15XSame as Gemini 10X. 15.5" carriage

5599.00

APPLE COMPATIBLEDISK DRIVESFAMOUS MULTIPLEXDISK DRIVE

5229.001 year full warranty.Features: Apple compatible Attractively packaged Profes-sionally built and tested Canadian Made. We believethat Muitif lex put out more drives in the last year thanail other Canadian manufacturers combined.

Note: For $199 we offer 120 day warranty. Howeverfor 10% more get a full 1 year warranty.

300 BAUD MODEM foryour APPLE 579.00Auto Answer, Dial, Direct, Con. Plugsright into your Apple, comes with soft-ware.

1200 BAUD EMP MODEM5419.00

POWER TYPE LETTERQUALITY 5639.00 18 CPS bidirectional logic seeking. 96 Petal Wheel

TTX Letter Quality12 CPS Daisy Wheel 5499.00EPSON FX 80 $689.00EPSON FX 100 $979.0oEPSON RX 80 5395.00Multiflex parallel Interface forApple or IBM $ 69.00

Cherry 5159.00Maxiswitch $159.00

IBM COMPATIBLE KEYBOARDIBM Compatible Disk DriveSA455 $228

CASES FOR YOURIBM Compatibles Hinged top cases allowing easy access

by opening top half of the case $74.95 Standard Sliding Cover Case $69.00

Hinged Case with 90W (max.) PowerSupply with fan $178.00

As above with 175W (max.) Power Supplyand fan $228.00

MonitorsZenithDataSystems

BEST SELLER ZVM 122A 12" diagonalscreen non -glare amber display composite input 25lines x 40/80 characters $139.00BEST SELLER ZVM 123A 12" diagonalscreen non -glare green display composite input 25lines x 40/80 characters 5129.00ZVM 133 13" diagonal screen RGB input 25lines x 80 characters 640 x 240 pixels green screenonly switch 16 colours including PC brown

$799.00

APPLE MACKINTOSH$2549.00

Hard Disk DriveSeagate (industry favoured)10 MEG. slimline 5989.0010 MEG Seagate, slimline driveand hard disk controller. Thiscontroller can handle up to two10 MEG had drivesLowest Price of

51,249.00Cable extra 538.00

MEMORIES, At prices youcan't forget! All primestock and we guaranteethe best price.4116 150 or 200ns $ 1.394164 150ns 5.9941256K 150ns $37.002114 200ns 1.896116 150ns 7.992716 450ns 4.992716 300ns 5.992732 350ns 6.992764 300ns S 9.9527128 300ns $21.95

Peripherals for your Apple:Z80 $ 49.0080 x 24 Video Card withSoft Switch 5 69.0016K RAM Card $ 49.00128K RAM Card 5159.00Parallel Card with Cable 5 65.00Serial Card 69.00Apple Programmer $ 65.00

AMDEK COLOUR 3+ $389.00RGB Monitor 90 DayRCB Card for Apple 2 +, or 2 E 599.00

Special Parts for yourIBM & Apple CompatiblesPrices good till January, 19858087 $245.008088M $22.008237A-5 $23.958250 $14.998253A-5 9.958255A-5 $12.998259A $ 9.958284A $12.508288 $22.00NEC765/8272 Equiv. $29.0074CS322 $ 7.9962 Pin Card Edge Connectors 2.595 Pin Din Connector S 1.70100ns Delay Line 8.956502 CPU 5 5.99Z80A CPU 5 5.2968A45 CRT cont. $10.79TMS99532 FSK Modem $25.95

All Parts in our new 24 page catalogue except Memories and other parts which are advertised on this page are 10% Off, for any stu-dent, bulk order discounts, can be arranged!

Mail Order phone (416) 252.5285. Make sure you have our New Fall 1984 catalogue available in all November 1984 issues of ETI andComputing Now! magazines. If you need a catalogue, just call us and we will get you one for Free.

Electronics Today January 1985 Circle No. 38 on Reader Service Card 3

SURPLUSTRONICSwe will not be undersold

Thanks to you and all our customers, our low-cost, no warranty policyhas worked beyond our belief and at the same time saves you a FORTUNE. Butyou haven't seen anything until you read this ad!NOTE: All prices on this page are final sale prices: NO warranty, NO returns, NO refunds BUT GIGANTICSAVINGS. If you want a 120 -day warranty, all you have to do is ask and pay somewhat more.

UNHEARDOF PRICE!8088Computer$11349All parts prime quality, j ii111111111111111

no design compromisesFully assembled and /4,,,tested Includes: 8088 motherboard with 64K Quality Cherry Keyboard Sturdy, quality case 90W max power supply with fan Colour Video board Floppy controller with provision of (but not

including) RS232 and real time clock. One SA455 DS,DD Shugart 5'/4 inch disk

drive Motherboard completely socketed with AMP

socketsFor the price of $1349 you get a blank 2764 EPROM, but payextra $55 and get the Phoenix Software Bios!

Monitor notIncluded

PERIPHERAL CARDS FOR YOURAPPLE & COMPATIBLEAssembled, flow-soldered/cleaned and 100% tested16K RAM Card $49.9580x24 video card $69.95Z80A Card $47.00Parallel Printer Card (cables extra) $49.95128K RAM Card with 64K $99.00128K RAM Card with 128K $139.00EPROM Programmer with Software(programs 2716, 2732, 2732A, 2764)

$63.00

8" Floppy Controller $79.00Modem $78.00Autoanswer/autodial, touch tone or pulse dial. Plugs rightinto the system.

Apple Compatible Disk Drives (SA390) . $229.00Case with numeric keyboard $129.00Power Supply (Hydro Approved) $65.00

IBM is a registered Trade Mark of IBM Canada LimitedApple is a registered Trade Mark of Apple Canada Limited

PERIPHERAL CARDS FORYOUR IBM AND

COMPATIBLE COMPUTERColour Video Board $178.00Composite video or RGB VideoFloppy Controller $139.00Handles up to four 5.25 inch DS,DD IBM compatibledrives. Provision for (but not included) clock andserial port.Floppy Controller with RS232 . . . $159.00As above but with RS232 interface.Floppy Controller w. clock/RS232 $188.95As above but with real time clock/calendar with a bat-tery backup and clock software.

Parallel and Game Port Card $65.00Cable and connector extra.Peripheral Interface Card $139.00Includes two serial ports, parallel port, game portand provision for (but not including) real time clock.Clock/Calendar Option $29.00With battery backup. Price is extra.256K & Multifunction BoardIncludes: Serial port, parallel port, game port, provi-sion for optional real time clock/calendar andsockeed for up to 256K RAM.With 64K RAM $189.00512K Board -Socketed for 512K including:64K RAM $179.00256K RAM $365.00512K RAM $599.00IBM Compatible Disk Drives $229.00Brand New, fresh from factory. Shugart SA455 40 track,double sided, double density Slimline. We have ordered10,000 from Shugart - that is why we can pass the savingson to you.IBM Compatible KeyboardsBrand NewMaxiswitch $149.00Cherry $159.00

Cases - High QualityConventionai SlkIng type 559.00Hinged at two points allowingyou easy access 569.00Special:Conventional Case with 90Wmax power supply and fan $169.00Hinged Case with power supply $179.00

Huge variety of Surplus stock at low, low prices. Newshipments arriving. No reasonable offers refused.Prices subject to change without notice!

Mall Orders add $5.00 minimum for shipping &handling. Ontirlc residents add 7% P.S.T. Visa,Mastercard and American Express cards ac.cepted: send card number, expiry data, name ofbank and signature. Send cerified cheque ormoney order, do not send cash.

Surplustronics, 310 College Street, Toronto, Ontario, M5T 1S3Circle No. 8 on Reader Service Card

More lines to serve you better

(416) 960.1350

1111=1"0-=....,,-...:,,,,--

i.k:31----1[1IIII..

\118I

Our CoverThe ECS6 portable 6502accompanies the pro-ducts reviewed in thisissue: a plotter, a lightpen, circuit software, anda modem; photos by BillMarkwick.

Audit Bureau of Circulation

Electronics Today is Published by:Moorshead Publications (12 times a year)Suite 601, 25 Overlea Blvd.Toronto, Ont. M4H 1131(416) 423-3262

Editor: William MarkwickEditorial Assistant: Edward ZapletalDirector of Production: Erik BlomkvvistCreative Manager: Ann RodriguesProduction: Douglas Goddard

Neville WilliamsNaznin Sunderji

Circulation Manager: Lisa SalvatoriAdvertising Director: Omar VogtAdvertising (Que.) John McCown & Associates

(514) 735-5191Advertising (B.C.) (604) 688-5914

Publisher: H.W. Moorshead; Executive Vice -President: V.K. Marskell; General Manager:S. Harrison; Controller: B. Shankman; Accounts:P. Dunphy; Reader Services: C. Wyatt, S. Halla-day, H. Brooks, R. Cree; Advertising Services:D. Whitehead

Newsstand Distribution:Master Media, Oakville, Ontario

Subscriptions:$19.95 (one year), $34.95 (two years). For US add$3.00 per year, other countries add $5.00 per year.Please specify if subscription is new or a renewal.

Postal Information:Second Class Mail Registration No. 3955. Mailingaddress for subscription orders, undeliverablecopies and change of address notice is:Electronics Today International, Suite 601, 25Overlea Blvd., Toronto, Ontario, M4H 1131

Printed in CanadaMoorshead Publications also publishes Computing Now!,Computers in Education, and Software Now!.

Advertiser's IndexActive Components Sales Corp 55

Advance Interface Electronics Inc. 12

BCS Electronics Ltd 11, 56, 57, 61Brunelle Instruments Inc. 7

Computer Parts Galore 28, 29Cyprus Products Inc 64Daetron 53

Dana's Computer Discount 60EDG Electronic Distributors Inc. 8, 9Electronic Control Systems 31

Exceltronix 2, 3Electronics Book Club 33Gladstone Electronic Supply Co. Ltd 63KB Electronics 35

Kaientai Electronics Merchants Ltd. 53

Kitstronic International Ltd. 27McGraw Hill 25Metermaster 37Orion Electronics Supplies Inc. 40Protec Microsystems Inc. 59Seagrams Distillers Ltd., 62Su rpl ust ronics 4

Electronics Today January 1985

ElectronicsTodaJanuary 1985

VoL 9 No. 1 ISSN 07038984

Canada's Magazine for Electronics Et Computing Enthusiasts

IR III 011111111 I;11111hii I

IR 111

14 Eat NMIECS6 Review, p. 34 Hammond Radio, p. 38

FeaturesIndex 1982-84Plasmon Solar CellsComputing Today: Projectile MotionHammond Radio MuseumElectronics in Action

16

26

30

38

46

ReviewsCosmic Printer/Plotter 10

Tech -Sketch Light Pen 13EMP 1200A Modem 24

ECS6 Portable Computer 34ACNAP Circuit Design Software 58

ProjectsAnalog Capacitance Meter 22

RS232 Breakout Box 45

SeriesDesigner's Notebook: Customised ICs 20Configurations: Multivibrators 50

Columns, News, and InformationFor Your Information 6 Computing Now! This Month 43Software Now! This Month 14 Next Month 44

Back Issues 19 Subscriptions 44

Circuit Ideas 41 Product Mart 48

Order Form 43

5

For Your InformationCopyrightAll material is subject to worldwide copyrightprotection. All PCB patterns are copyrightand no company can sell boards to our designwithout our permission.

LiabilityWhile every effort has been made to ensurethat all constructional projects referred in thismagazine will operate as indicted efficientlyand properly and that all necessary com-ponents are available, no responsibility what-soever is accepted in respect of the failure forany reason at all of the project to operate effi-ciently or at all whether due to any fault in thedesign or otherwise and no responsibility is ac-cepted for the failure to obtain componentparts in respect of any such projects. Furtherno responsibility is accepted in respect of anyinjury or damage, caused by any fault indesign of any such project as aforesaid.

Editorial QueriesWritten queries can only be answered when ac-companied by a self-addressed, stampedenvelope. These must relate to recent articlesand not involve the staff in any research. Marksuch letter ETI Query. We cannot answertelephone queries.

BindersBinders made especially for ETI are availablefor $9.25 including postage and handling. On-tario residents please add provincial sales tax.

Back Issues and PhotocopiesPrevious issues of ETI Canada are availabledirect from our office for $4.00 each; pleasespecify by month, not by feature you require.See order card for issue available.

We can supply photocopies of any articlepublished in ETI Canada; the charge is $2.00per article, regardless of length. Please specifyboth issue and article.

Component Notation and UnitsWe normally specify components using an in-ternational standard. Many readers will be un-familiar with this but it's simple, less likely tolead to error and will be widely usedeverywhere sooner or later. ET1 has opted forsooner!Firstly decimal points are dropped andsubstituted with the multiplier: thus 4.7uF iswritten 4u7. Capacitors also use the multipliernano (one nanofarad is 1000pF). Thus 0.1 uFis 100nF, 5600pF is 5n6. Other examples are5.6F = 5p6 and 0.5pF = Op5.Resistors are treated similarly: I.8Mohms isIMP, 56k ohms is the same, 4.7kohms is 4k7,100ohms is 100R and 5.60hms is 5R6.

PCB SuppliersETI magazine does NOT supply PCBs or kitsbut we do issue manufacturing permits forcompanies to manufacture boards and kits toour designs, Contact the following companieswhen ordering boards.

Please note we do not keep track of whatis available from who so please don't contactus for information PCBs and kits. Similarly donot ask PCB suppliers for help with projects.

K.S.K. Associates, P.O. Box 266, Milton,Ont. L9T 4N9.B-C-D Electronics, P.O. Box 6326, Stn. F,Hamilton, Ont. L9C 6L9.Wentworth Electronics, R.R. No. I Water -down, Ont. LOR 2H0.Danocinths Inc., P.O. Box 261, Westland MI48185 USA.Arkon Electronics Ltd., 409 Queen Street W.,Toronto, Ont., M5V 2A5.Beyer & Martin Electronic Ltd., 2 Jodi Ave.,Unit C, Downsview, Ontario M3N I HI.Spectrum Electronics, 14 Knightswood Cres-cent, Brantford, Ontario N3R 7E6.

New CMOS/NMOS SpecialFunctions Data ManualMotorola Logic and Special Func-tions Division announces the newCMOS/NMOS Special FunctionsData Manual. A complete com-pilation of product specificationand application information, thiscomprehensive book covers morethan 60 Special Function VLSI in-tegrated circuits offered byMotorola. It consists of elevendetailed chapters, includingseparate chapters for each familyof devices: CMOS ADCs/DACs,CMOS Decoders/Display Drivers,CMOS OperationalAmplifiers/Comparators,CMOS/NMOS PLLs/FrequencySynthesizers, CMOS Remote Con-trol Functions, CMOS SmokeDetectors and Miscellaneous Func-tions.

Pricing for the new MotorolaCMOS/NMOS Special FunctionsData Manual is $1.60 each inquantities of 1-9; $1.35 each for10-24; and $1,20 each for 25 ormore. Copies of this data book canbe obtained by calling the nearestMotorola components dealer, orby sending the appropriate pay-ment to Motorola's LiteratureDistribution Center, BroadwayBuilding #1, 616 W. 24th St.,Tempe, AZ 85282. Request booknumber DL130.

Sony Tokyo announced that it willmarket in Japan, starting October21, a high -density digital televisionsystem, which incorporatesdouble -speed non -interlace scann-ing, and a multi -functional digitaltelevision receiver called theDigital Canvas.

The DSGIO is a non -interlacescanning unit which doubles thenumber of scanning lines (NTSC525 lines) by means of digital inter-polation to reproduce a bright andfine-grained picture without lineflickers. This digital scan converterconverts video and RGB signals in-to RGB double -speed non -interlace signals (31.5kHz).

The KX-14HD1 multi -scancolor monitor is so designed toreproduce the signal informationsupplied from the digital scan con-verter in double -speed non -interlace scanning. Its newly -developed Auto Tracking ScanSystem makes it possible tomonitor a wide range of scanningfrequencies (from 15 to 34kHz).This color monitor thus can be us-ed not only with a videotaperecorder and a videodisc player butalso with a personal computer(24kHz) and a CAPTAIN terminal(31.5kHz), just to name a fewtypes of visual equipment.

Also, in the Test Equipmentreview, the photographs of theSony/Tek scope and the HamegHM208 scope were interchanged.Our apologies to the distributors.

Tri-State Databox

Ideal for data equipment users,communications companies, ser-vice organizations, equipmentmanufacturers and hobbyists, thepocket-size self-contained Tri-State Databox simply plugs in bet-ween the data terminal equipmentand either the modem or corn-municaitons equipment.

Dual -in -line switches permitinterruption of any of 24 interfacesignals for fast and simple loca-tions of the source of trouble. Tri-state LED's show RED for positivesignals, GREEN for negativesignals, and OFF for invalidsignals. A separate 5 -position dip

switch allows lines 2 and 3 to beswapped for modem reversal, or toapply positive voltage for test ap-plications.

The Datacom Tri-StateDatabox is battery operated andincludes a low battery indicator.Units are available in stock atauthorized ACA distributorsacross Canada. Contact: Ms. KellyWiddes, Allan CrawfordAssociates Ltd., Test & Measure-ment Division, 6503 NorthamDrive, Mississauga, Ontario L4V1J2,(416) 678-1500.

Circle No.58 on Reader Service Card

New Battery Holder Accepts Most 3V Coin CellsThe new BH1000 single cell bateryholder from Memory ProtectionDevices Inc. will accept most 3 -voltlithium coin cells up to 24mm x3.0mm in size. The holder may bepermanently soldered on a PCboard for reliable memory protec-tion.

The coin cell clips right in foreasy installation and maintenance.BH1000 is made of tough, hightemperature molded Valox withspring -tempered, stainless steel,nickel plated contacts that aredesigned to ensure correct polarity.It is also low profile for high densi-ty packaing.

For a sample and complete sep-cification on the new MPDBH1000 single -cell battery holder,contact: Memory ProtectionDevices Inc., 320 Broad Hollow

Road, Farmingdale,(516) 454-0340.Circle No.57 on Reader Service Card

NY 11735.

6 Electronics Today January 1985

New Miniature Retro-Reflective PhotoelectricSwitchesELECTRO announces availabilityof their new line of PHOTO-TROL® Model LR200 Retro-Reflective Photoelectric Switches.Units can be powered with eitherAC or DC voltages. AC modelscontain a solid-state triac switch.DC models are solid-state, open -collector switches and are pro-tected against polarity reversal,and/or short circuit. Among thesmallest (less than 3/4 -inch in dia.),PHOTO-TROL® photoelectricswitches are completely self-contained, utilize pulsed infraredenergy, and are unaffected by am-bient light allowing full use in in-dustrial environments. Features in-clude: LED indicator for switchstatus; housings meeting NEMA 1,

After two years, we have an issuewith no Roger Allan science ar-ticles other than the Electronics inAction column. After doing an ex-cellent job of covering science forus, Roger has accepted the job ofeditor of Computers in Education,another Moorshead publication.Our best wishes to Roger in hisnew career.

2, 3R, 3S, 4, 4X and 13 standards.Electro Corporation is

represented and stocked by AtlasElectronics Limited, 50 WingoldAvenue, Toronto, Ontario.Branch sales offices are in Mon-treal, Ottawa, Winnipeg, Calgary,and Vancouver, with distributorslocated across Canada. For furtherinformation please contact, BrucePetty at (416) 789-7761.Circle No.60 on Reader Service Card

The editor would like to point outthat the review of the PsionOrganiser in last month's issue waswritten and typeset before thepublisher decided to sell the Psionas a limited -time reader offer. Toobad, he adds, I could have held outfor thousands of dollars.

Aerosol PCB Cleaning SolventMicro Care aerosol cleaningsolvents remove flux from printedcircuit boards thoroughly by com-bining soaking, scrubbing andflushing in the same operation.

Designed with a comfortable"trigger grip" that gives theoperator added control withouthand fatigue, the Spray-Thru-Brush attaches directly to the valveorifice on the can of Micro Caresolvent. This sturdy hand-held at-tachment allows remote spraying

After 21 years of faithful servicean old war horse is being put out topasture. This Canadian recordachieved at Chalk River NuclearLaboratories by their PDP-1 com-puter, one of the first computers tobe used in Canada on-line with ex-periments.

The PDP-1 was purchasedfrom Digital Equipment ofCanada Limited, and in its time itprocessed raw data from the EN -1,the world's first tandem ac-celerator or "atom smasher,"which was delivered to Chalk Riverin the summer of 1958. Then, fiveyears later PDP-1 came aboard, tobe added to the Laboratories'research facilities.

In 1966 EN -1 was dismantledand sold for one dollar to theUniversity of Montreal. It wasreplaced by the powerful new MPtandem accelerator, originallycapable of operating at 10 millionvolts, later upgraded to 13 MV.The PDP-1 was hooked up to thenew accelerator, and it providedfaithful service from that time.

The computer was replacedbecause maintenance became aproblem. In the fast -paced worldof computers the normal servicinglifetime is 5-10 years. The PDP-1used germanium transistors, whichare now not available, and itbecame more and more difficult tokeep it operating.

The PDP-1 had a memory of32,000 18 -bit words and a memorycycle time of 5 microseconds. Itcost $439,000 21 years ago, butcomputers have since developed tothe stage where even a $300 homecomputer has the same memorycapacity and a shorter 1 microse-cond cycle time.

The contrast as to size bet-ween the PDP-1 and the Perkin-Elmer 3230 which replaces it iseven more striking than this costcomparison. The PDP-1 takes upabout as much space as a half adozen home freezer units. The cen-tral processor and memory boardsof the 3230 are about the size of anAM/FM tuner.

The mighty mite, however,has a memory of a million 32 -bitwords, and can support fourmillion in totoal. The 3230 com-puter will be part of the newtandem accelerator superconduc-ting cyclotron complex, readingdata from new experiments whichwill be possible with the vastly im-proved research facility.

In its long and useful service,says CHALK TALK, the CRNLnewsletter, the PDP-1 has playedits part in many contributions toscientific knowledge, ranging fromphysics experiments to those of in-terest to environmental scientists,archaelogists and engineers. Of im-mediate practical importance havebeen radiation damage studies, thedevelopment of new radiationdetectors and the pioneering of on-line and automatic data analysissystems.

A generation of physicists atChalk River and in universitieswho have used the tandem ac-celerator will perhaps mourn thepassing of a link with the past, butits successor will be an enormousimprovement capable of playingan expanded role in discoveries yetto be made with exciting newfaciliaties about to come intooperation.By David P. Dempster

Electronics .1.oda) .lanuar 1985

up to three feet from the mastercan. It also provides flexibility forbench operations, permitting twoor more operators to use one can.

For more information aboutMicro Care aerosol solvents, con-tact: Larry H. Heisler,GENESOLV Solvent SystemsGroup, Allied Corporation, P.O.Box 1139R, Morristown, NewJersey 07960, or call (201)455-6751.Circle No.59 on Reader Service Card

continued on page 18

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New Sinclair QL* 32 -bit processor* 128K memory* two built-in microdrives* high resolution colour

Includes software:word-processingdatabase managementspreadsheetgraphics

The Sinclair QL revolutionizes thecomputer revolution. It offers the utmostin performance, speed and power at theremarkably low price of only $799.95.

The QL is a full-size computer designedaround the most powerful and advancedmicroprocessor yet created for the per-sonal computer: the Motorola 68008.With 128K RAM, expandable to 640K.Two built-in Microdrives. Networking. Afull-sized QWERTY keyboard. And itsown operation system - QDOS - whichaccomodates windows and even multi-tasking. High resolution colour or blackand white display, on either monitor orTV. Two RS -232C serial interfaces.Joystick cursor control.

That's just the hardware. The QL alsocomes with all the software you need toget started right away doing useful work.Word processing. Spreadsheet. Graphics.Database management. A powerful set ofprograms as sophisticated and as easy touse as any on the market.

Powerful ProcessorsThe 68008 is already the favourite choiceof software designers for its speed andflexibility. Its 32 -bit architecture virtuallygurantees the QL will never becomeoutdated, and that wide software choiceswill be available in the future.

A second processor, an Intel 8049,controls the keyboard, generates thesound, and acts as an RS -232 receiver.

New Operating SystemQDOS resides within the QL's 32K ROM.It is a single -user multi -tasking, time -sliced system using Sinclair SuperBASICas a command language. Multi -taskingallows you to run several programmes in-dividually and simultaneously, a featurenormally found on computers costing atleast 10 times as much as the QL.

128K Memory ExpandableThe QL comes with a generous 128K ofinternal RAM, more than enough for thelargest programmes you'll want under or-dinary circumstances. An optional expan-sion board can turn your 128K into 640Ksimply and inexpensively.

Professional KeyboardThe QL keyboard is designed for fast, ac-curate input of data and programmes. It isa full-size QWERTY keyboard, with 64keys, including shift keys, five functionkeys, and four separate cursor controlkeys. Key action is positive and precise.

The MicrodrivesThe QL's cartridge tape storage system isvery much a part of the Sinclairrevolution. For the first time floppy diskperformance has been matched in acompact medium far less expensive toown. Depending on programme length,load time is 10 to 20 times faster thancassette. The rate of data transfer isactually a little faster than floppy disk.You can store up to 50 files, or 100K, percartridge. Microdrive maintains an indexso you can see exactly what's on anycartridge.

The QL has two built-in Microdrives, withexpansion of up to six more.

A New BasicThe Sinclair SuperBASIC combines thefamiliarity of BASIC with a number ofmajor developments which allows theQL's full power to be exploited.Procedure facility allows code to bewritten in clearly -defined blocks.Extendability allows new procedures to beadded which will work in exactly the sameway as the command procedure built intothe ROM with which you're alreadyfamiliar. Constant execution speed meansSuperBASIC won't get slower as yourprogrammes get larger. Instead, longprogrammes run much faster than withother Basics.

Incredible Extra FeaturesThe QL features built-in networkingcapability for up to 64 QL computers. Setup local area networks of QL computersto swap information, ideas and program-mes, shared over the network at 100Kbaud.High resolution graphics? Up to 512 x 256pixels (4 colour), 256 x 256 (8 colour).ROM expansion? The QL will accept anadditional 32K ROM cartridge.

Included QL Pr(Four fully -interactive programmesdesigned especially for the QL. Datafrom one programme can betransported to another. For example.

Word-processingQL Quill word-processing gives an exact scree]display of how your printed work will appearHelpful prompts are available on -screen to stetyou through every word-processing taskFeatures include automatic word-wrap ancparagraph indentation. Delete text bycharacter, word, line or by block. Search andreplace. Cut and paste, set tabs, margins, linespacing, headers and footers, view widedocument. Combine data from other QLprogrammes. Boldface, superscript, subscripts,underline, hyphenate, overwrite. And more!

SpreadsheetQL Abacus makes simultaneous calculationsand "what if- model -construction easier thanthey have ever been. Refer to rows, columns,and cells by names, not just letters andnumbers. Function keys can be assignedcalculations with a single key -stroke. On screenprompts and Help menus simplify operations.You can link spreadsheets, use multipitwindows, vary column width and justificatiotof text. Scroll windows jointly or separatelyhorizontally or vertically. There are many morefeatures!

32 -bit processor architecture128K RAM, and QDOScombine to give theQL the performanceof a mini -computerfor the price of a micro.

fessional Software!figures from the spreadsheet can betransferred to the Graphicsprogramme for an instant visualpresentation!

Database managementQL Archive is an extremely sophisticated yeteasy to use filing system using a language evensimpler than BASIC. You can define relation-ships, extract data and reorganize it, dostatistical and accounting calculations andmore. Screen editor allows you to design yourown screen and format reports. Procedure anprogrammes may be written and saved forrepeated use. Choose from 84 command wordsfor queries, cross-reference entries, and searchany number of files. Easy -to -use sinceeverything is performed within the frameworkof familiar information prompts and Helpmenus.

GraphicsSpectacular colour graphs are easy to createwith single key -stroke commands. QL Easeldoes not require you to format display beforeentering data; it handles design and scalingautomatically or under your control. There arenine graph styles. Text can be added or alteredas simply as data. QL Easel can alsomanipulate and evaluate data using a series ofcommand math functions and formulas.

only $799

Getting the most fromyour QLYour QL is supplied with a comprehensiveset of manuals that make learning not on-ly painless, but truly enjoyable. The QLmanual includes a SuperBASIC referencemanual, programming tutorial, and com-plete guides to the software. The manualalso contains details of QL's comprehen-sive 90 -day warranty, and service infor-mation.

Here is what you get:Your QL comes complete with powersupply, cables, manual, software andblank Microdrive cartridges. You will alsoreceive information on the Canadian QLUsers Club - available only to purchaserswithin Canada. Please remember as wellthat only QL's purchased in Canada canbe serviced under the terms of thewarranty. All orders will be acknowledgedby return mail. Due to anticipated heavydemand please allow 4-6 weeks fordelivery.

EDG offers a 7 -day money backguarantee on QLs purchased directly fromus. The QL may also be available throughlocal dealers in 1985.

Future DevelopmentsFuture QL products under developmentinclude a "C" compiler. 68000 assembler.Terminal emulator (that will allow you totie your QL into a mini or even a main-frame computer). A 0.5Mb memory ex-pansion board. Analogue -to -digital con-verter that could turn your QL into ahome sound studio. Winchester hard diskinterface. Parallel printer interface.IEEE -48 interface for engineering andscientific applications.

How to Order your QLBy Mail:Complete the coupon and mail it to EDGElectronic Distributors Inc. at the addressshown below. Enclose your credit cardnumber or cheque. (Certified chequeNOT required)

By Phone:Call (416) 636-9415. Order lines open 7days a week, 24 hours. Have your VISAor MASTERCARD ready. Call eveningsor weekends for lower telephone rates.Queries can be answered only duringbusiness hours.Sorry - no personal shopping.

Mail to: EDG Electronics Distributors Inc.3950 Chesswood Drive,Downsview, Ontario.M3J 2W5

Please send Each Total

Sinclair QL Computer $799 95

Shipping & Handling 15 00

Ont. res. add 7% PST 57 05

TOTAL

Enclosed is: Charge to:Cheque Li Money Order O visa Li Mastercard

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Review

Cosmic CM P-9022Plotter PrinterA new compact four-colour plotter/

printer with some impressivequalities and a low $249.95 price -tag has landed on our shores.

There was a time when things such as plot-ters, as well as printers, were luxuries thatonly the higher computing gods could wellafford. The years have passed and the ageof miniaturization has changed all of that.Not looking much bigger than a printingdesktop calculator, the CMP-9022four-colour plotter/printer is proofpositive that good things come in smallpackages.

At First GlanceSetting up the 9022 is no big deal. Youwill need a Centronics parallel interfaceand cable for making the necessary con -

By Edward Zapletalnections to your favourite micro. Oneminor problem encountered was a lack oflocking clips for the interface cable on theplotter itself. Each time we tried to insertthe cable into the plotter it would popback out. A call to Gladstone Electronicssolved the problem in a flash. The par-ticular unit which we were in the posses-sion of had been dismantled earlier and aspacer was left out upon reassembly. Werectified the problem with masking tape.

A definite plus for this machine is itsuse of regular paper as opposed to ther-mal. The 114cm-wide by 55m -long paperfed easily into the back of the unit, but the

holder containing the roll seemed to be abit shakey when in position. An attemptto turn the unit over for a look at theunderside resulted in the quick departureof the holder from the plotter.

On the top of the 9022 you will findthe usual printer -like button switches: linefeed, colour select, and pen change as wellas paper end and power indicator lights.The underside reveals three slide switchesfor controlling carriage return, 40/80character width, and ASCII/Japanesecharacter sets. The Centronics cable fitsinto the side as does the power cord.

The pen holder, which contains thefour 2.5cm-long ballpoint cartridges, issurprisingly small. Changing the pens is asnap and above all there is no mess. Thecolours are sharp and there didn't appearto be any skipping as some ballpoints tendto do.

Powering up the unit caused it to gointo its self -test routine; printing four col-oured squares across the paper. If youkeep the line feed button depressed whileadministering the power switch the 9022will etch out the four squares as well as itsentire set of 96 ASCII characters.

BASICally SpeakingThe unit is capable of operating in eithertext or graphics mode and the quality ofboth is superb. The smallest letter produc-ed was approximately 1 mm in height andit was very readable. The resolution of thegraphics is 0.2mm per step according tothe specifications; I'd hesitate to arguethat point because a circle produced bythe 9022 actually looked like a circle.

Programming is no problem since allcommands are incorporated into standardBASIC. There are four standard controlcodes used in the text mode: backspace,paper reverse, switch to graphics, andnext colour. The CHR$ function is usedto activate these, and there are otherswhich you can get by experimenting (or bylooking at the ASCII chart in the back ofthe manual).


The graphics mode contains 13

graphics commands which include: colourchange, pen movements (with or withoutdrawing), character size, and rotation ofprinting. Depending on the version ofBASIC you happen to be using, the printstatement used to initiate the commandsmay be either PRINT or LPRINT. On theApple version a PR#1 is necessary to ac-tivate the interface before any printing orplotting is attempted.

The following is an example of a sim-ple program which moves the pen to aspecific starting location on the paper,sets the origin (0,0) of the X and Y axesusing the I command, and proceeds todraw a triangle using the "D" command.

10 REM *** I -Command ***20 PR#130 PRINT CHR$(18)40 PRINT "M100,-240"50 PRINT "I"60 PRINT"D100,170,200,0,0,0"

Line 20 of the program activates theplotter (Apple ver.) and line 30 turns onthe graphics mode. The print statement inline 40 tells the plotter to move the pen toa location 100 units to the right of the leftpaper edge and 240 units down. This willappear as a diagonal motion when theprogram is executed. The "I" commandsets the current pen location to the point0,0 (origin) in preparation for drawing.The numbers following the "D" com-mand are actually grouped in pairs (coor-dinates) from left to right and are thedestinations to which the pen will draw.For instance: 100,170 signals the pen todraw a line to a location 100 units to theright and 170 units up from the startingpoint and so on.

If you're not quite familiar with allthis X and Y axis stuff then you mighthave to read up on your geometry. Don'tpanic though, if this all sounds too com-plicated the best way to get acquaintedwith the 9022 is by playing with it.

The ManualJust a word about the instruction manual.The benefits from owning this dandy littleplotter are actually two -fold. First, youbecome proficient in creating greatgraphics, and second, you will be com-pletely fluent in Taiwenglish.Taiwenglish? This is not a newphenomenon but one which has beenaround as long as imported goods fromthe Far East. It's actually a cross betweenTaiwanese and English resulting fromdirect translation to the latter. It seems asthough the good folks over there aredetermined to write instruction manualsthis way. They are very entertaining toread, but it may be difficult to understandwhat it is that they're trying to tell you.Enough said.Electronics Today January 1985

Wrap It Up PleaseThe 9022 really has to be seen to be ap-preciated. Its sleek compact design andlow price make it ideal for anyone wantingto get into computer graphics. The $1000dot matrix graphics printer is no longerthe only route to go for the home com-puting enthusiast who wants to generatesimple graphics, in colour to boot!

Quick IndexPrice $249.95Available: Gladstone Electronics

1736 Avenue Rd.,Toronto, Ont.M5M 3Y7(416) 787-1448-800-268-3640 fortelephone orders.

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Circle No. 30 on Reader Service Card II

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$190.00

NEC SPECIAL ICsAPD 765A ( = 8272) $22.00APD 7201C = 8274) $22.00f,t,PD 7210C $26.00APD 7220D $46.00

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IBM® compatibleKeyboard

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IBM Verbatim/HITACHI/NEC64K D -RAM UARTS compatible Datalife®

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AY3.1015D $7.00(Single + 5V)

PANASONICJA551.2

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AY5.1013A $5.90 DISK DRIVE for HP' & Macintosh'5215.00

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Z80A- DMA $15.00 * printers * 10 -MB CMI.5412 drive with WesternZ80A- DA RT $10.50Z80A-P10 $ 5.20 * AC power line filters Digital controller 51099.00/setZ80A-S10/0 $15.00Z80ASIO/1 $15.00Z80A-S1012 $15.00

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12 Circle No. 31 on Reader Service Card. Electronics Today January 1985

Review

Tech -Sketch Light Pen

Turn your TV into avideo canvas and keepthe kids from drawingon your freshly -paintedwalls.

By Edward Zapletal

LIGHT PEN technology is certainly notnew in the world of computing; designengineers have been using them to createprototype drawings of everything fromcars to integrated circuits. Lately, though,with the declining cost of peripherals formicrocomputers , the light pen is finding aplace in the home computer graphics mar-ket. The latest entry into that market is theTech -Sketch Light Pen from Tech SketchInc.

To be perfectly honest, there really isn'tmuch to a light pen except a cable, push-button switch, and a photocell. The realguts behind the whole thing is the soft-ware. The Tech -Sketch comes packagedwith the Micro Illustrator software fromElectronics Today January 1985

Annff

Erase

Frame

Storage ttirror

Island Graphics in formats for: the AppleIIe, II+ , II, (and compatibles?), Com-modore 64, and Atari computers. We werefortunate enough that the Tech Sketchpeople bestowed us with an Apple versionfor this review.

Plugging InUpon its arrival, we eagerly unpacked thenecessary hard and software whichincluded the light pen, diskette, and inter-face card complete with an attachedjumper clip. By the way, the card isrequired only for the Apple versions and isconsidered an optional extra.

Lines

Circle1 if Fi

ttagnify

There is a choice of two slot locationsfor the insertion of the light pen interface.This is for Apple and clone users alikewho have few vacancies in the ol' slotmotel. The recommended location is inslot 5 with the jumper clip connected toresistor R8 (2k ohms) for the II or II + ,and R5 on the He. These resistors arelocated near the game 10 sockets and careshould be taken when connecting up tothem. If slot five is occupied, slot sevenwill do just fine, and the jumper is ignoredin this case. The reason for using thejumper clip, according to the Tech Sketchpeople, is because there is no direct con-nection to the video synch from slot five.

13

Tech -Sketch Light Pen

Micro IllustratorAs mentioned previously, the driving soft-ware for the pen is the Micro Illustrator.This is the same Micro Illustrator used inconjunction with the popular Koala Padgraphics tablet. For the purposes of put-ting the light pen and software throughtheir paces, I opted for an Apple II + moreout of necessity than availability. I hadoriginally planned, at this point, todescribe the difficulty encountered inmaking the whole thing work on an Applecompatible, but to be fair I will tackle thelight pen first. Technical difficulties willbe covered further on.

On booting the Micro Illustrator diskyou are first greeted with the usual titleand copyright information, in tech-nicolour of course. After you've satisfiedthe computer's request for the slot loca-tion, some minor housekeeping details arein order in the way of calibrating the lightpen's accuracy and speed of response.Once complete, you're on your way tobecoming another Van Gogh.

The Menu PleaseThe Micro Illustrator's menu is dividedinto three main sections: commands,brush set, and color sets. The commandsection contains 15 functions for drawingthe basic shapes such as lines, boxes, cir-cles, frames and so on. There are ninebrushes to select from, and there are atotal of 18 colours arranged in two sets ofnine. Strange things happen, though,when mixing colours from one set withthose of another. Drawing a white line(colour set 1) on a powder -blue (colour set2) background produced a red shadowaround the line. According to the manualthis is to be expected on the Apple com-puter.

One of the more interesting features ofthe Micro Illustrator is its rubber bandingcapability. Similar to Apple's Macintoshelastic software, this feature allows you tomanipulate the size of frames, boxes, cir-cles, discs, and rays for previewing pur-poses. By selecting the circle function,positioning the pen over the screen, anddepressing the button, you create a centrepoint for a circle. Moving the pen away fromthat point causes a rubber band -like circleto appear on the screen. When you'vedecided that your circle is just right,depressing the button freezes your master-piece.

Other features include ERASE, STOR-AGE, MAGNIFY, and ALIGN. The align-ment command is used in the event that thecursor no longer appears to be directlyunder the tip of the pen. This is actually thesame alignment function which sets up theMicro Illustrator at boot time.

The STORAGE command dumps youinto yet another menu where the CATA-LOG, DISK FILE UTILITIES, LOADing,14

and SAVEing routines are stashed. The diskutilities include the usual such as format,lock, unlock etc. Pictures can be saved orloaded to or from any DOS 3.3 disk.

Compatibility?Clone (klon), n. Biol. a group of organismsderived from a single individual by varioustypes of asexual reproduction. That's theRandom House Dictionary definition ofsomething that is supposed to be identicalin every way to the original.

After powering down a number of thetrusty Unitron 6502s here at the office, weproceeded to follow the instructions forconnecting up to an Apple compatible com-puter. 'The software,loaded without a hitchand everything looked rosey except for thefact that the light pen just wouldn't work.With the card in slot five and the jumperconnected to the equivalent of the R8resistor on the II and II + versions, therewas no action. Slot seven also proved to be ahopeless exercise. Meanwhile, the TechSketch people phoned to check on howthings were progressing. After explainingthe lack of success, we were instructed toreturn the pen for a replacement.

Our worst fears were realized when thenew pen arrived and yielded the sameresults as before. There was no way in theworld that this or any other Apple clonewas going to give in. The Tech Sketchpeople in New Jersey were very sym-pathetic and did their best to assist us, butthey were not able to offer any explana-tion for the incompatibility.

IncompatibilityIt should be noted here that the problem isnot necessarily with the Pen and/or inter-face, but rather with the type of machine towhich they are connected. After all, itworked as promised on the real Apple. Myoverall impression of the package is quitegood, although I question the usefulnessof light pens in the home market. Afford-able software limits most people to tinker-ing with colourful graphics on the familyTV set and more expensive design soft-ware is left to the higher gods in the man-ufacturing world.

Quick Reference

Price: $139.95 Apple version (incl.interface)$49.95 Commodore, Atari

Software: Micro Illustrator includedDistributor: Citation Software

1901 Logan Ave.,Winnipeg, ManitobaR2R OH6(204) 632-0559

Manufacturer _Tech Sketch Inc.26 Just Rd.,Fairfield, N.J.07006(201) 227-7724

This MonthIn

SoftwareNow!

MAC Data BasesA review of four data bases for theMacintosh.

Micro TypographerAdd text to your hi-res graphics.

B GraphA look at a gr.aphics package foretching out those charts andgraphs.

Copy ProgramsTwo copy programs for cloningPC software.

Flight SimulatorsGet off the ground without everhaving to get out of your chair.

CondorNot a story about the giant bird,but a look at a file managementsystem.

On Sale Now!


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$29.95COMPUTrivia is an exciting new Canadian software package designed to let you challenge your friends and family, giving hours ofenjoyable entertainment. Available for: the Apple II and 11c, Commodore -64, IBM-PC, PCjr. and their respective compatible types,COMPUTrivia is a deal at $39.95. But it's an even better deal if you order now from Moorshead Publications at this amazing one-timeoffer price of $29.95.

Questions from eight categories containing over 1300 trivia teasers are randomly selected by your computer or you can pick aquestion from your favourite topic. Also, no question will be repeated until all the questions have been used. Your home computerdoes all the work including keeping track of the scores of 2 to 6 players or teams. Set time -limits, give hints (or not), and settledisputes easily with the Error Menu.

Remember, this is a limited time offer and the LOW LOW price of $29.95 will not be offered again. Order yours now and enjoyhours of brain -picking fun with COMPUTrivia.

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Offer expires Feburary 15th 1985Please use this coupon or a photocopy to place your order

Electronics Today January 1985 15

::::::::::** :::::::::::::::::::.....-... ::::::........ :::::::::.1982

Features Month Page Errata

Loudspeaker Des. Princ. Pt. 2Big BangSL ElectronicsIndex 1981SignsIndustrial RobotsAmplifier ClassDBXShort Wave AerialsNi-CadsPerfect SoundGluonsSatellite ApplicationsFessendenShroud Of TurinFaster Than Light TravelDronesOptical Disk RecordsFibre OpticsLasers In Hi-FiLeptonsHertzElectronic OfficeThe Hall EffectMarconi30 Years Of Canadian TVIntroduction To 1 -ChingRogersTelidonUPC CodesCrossover NetworksStephensonElectronics In CarsParticle Beam FusionHistory Of Early RadioSupercooled Magnetic SensorsSolar Energy In CanadaFlat Screen TVFostex A-4 ReviewRadio AstronomySatellite TVHenry

Jan 10

Jan 23

Jan 39Jan 64Feb 35Feb 38Feb 61

Feb 64Feb 66Mar 25Mar 40Mar 41Apr 10

Apr 45May 13

May 2

May 39May 56Jun 10

Jun 51

Jun 39Jun 41

Jul 10

Jul 39Jul 51

Aug 10

Aug 22Aug 65Sep 9

Sep 18

Sep 46Sep 50Oct 11

Oct 27Oct 39Oct 48Nov 10

Nov 27Nov 32Dec 10

Dec 24Dec 55

Projects Month Page Errata

4 -Way Loudspeaker Jan 14

Movement Alarm Jan 33Temp. Controlled Soldering

IronFlash SequencerEnlarger TimerSound BenderMusic ProcessorCrystal MarkerNi-Cad ChargerReaction TesterBackground Noise SimulatorLow Power Pilot LightPower PackMicro Power Thermal AlarmSteam Locomotive WhistleAM RadioPhoto TimerTouch LampElectronic ThermometerElectroni^ DoorbuzzerAF Signal GeneratorSuper DiceLED Level MeterPhono Preamp

Jan 68Feb 23Feb 59Feb 75Mar 10 Feb 10

Mar 19

Mar 31

Mar 55Apr 26Apr 28Apr 29Apr 31

Apr 34Apr 49Apr 51

Apr 53Apr 55Apr 58May 41May 49May 71Jun 46


RouletteLight WandStylus OrganNegative Ion GeneratorSticks Drum BoxHeads And TailsScratch FilterVoltage Controlled Audio1 -Ching ComputerSemiconductor TesterSynthesizer I150 Watt AmpBody Work CheckerSynthesizer IIIntelligent Ni-Cad ChargerTerminalPest ControlSolid State ReverbSynthesizer IIIIntelligent TerminalRPM MeterContrast MeterSeries 5000 Preamp Pt. I

Hand Clap Synthesizer

Jun 31

Jun 54Jun 64Jul 16

Jul 31

Jul 37Jul 41

Jul 45Aug 24Aug 33Aug 39Sep 20Sep 26

ep 45Oct 18

Oct 43Oct 46Nov 17

Nov 22Nov 40Nov 49Dec 17

Dec 47Dec 59

Circuit Theory And Components Month Page Errata

Stores Survey

Micropower Circuits50 CircuitsInto Linear ICs Pt. 2CMOS CircuitsInto Linear ICs Pt. 34066B CircuitsCMOSInto Linear ICs Pt. 450 More CircuitsInto Linear ICs Pt.5The 'ScopeHigh Performance Op -AmpsAspects Of The 'ScopeDAC-ADC CircuitsXR2206Into Digital ICsVoltage Controlled PotsDolby CJunction FETs6500 CPUs

Jan

Jan

Feb

Feb

MarMarAprMayMayJun

Jun

Jul

AugSep

OctOctOctNovNovDec

Dec

23

45

10

69

45

61

18

31

65

15

60

24

50

13

31

62

69

54

59

20

28

Computers Month Page Errata

Acorn Atom Review Jan 36Acorn Atom Operating SystemReview Feb 29POKEing The ZX80 Feb 36Printers Mar 16ZX8 I Review Mar 35TRS-80 Model II Review Apr 38Electric Pencil Apr 63Voice Mailbox Apr 65Modems May 34U of T Computer Review May 44Xerox Computer Review Jun 35Heath/Zenith Computer Review Jul 22Osborne Review Aug 15

Light Memory Aug 18

Bulletin Board System Aug 44Hex Notation Aug 48TRS-80 Model III Review Sep 35Ace 100 Review Sep 60if800 Review Oct 23

1982-1983Computer

Panasonic Link ComputerBulletin Board UpdateApple III ReviewWhat Is CP/MThe Apple PiratesIBM PC ReviewMultiflex Review

1983

Month Page Errata

Oct 51

Nov 30Nov 35Nov 51

Dec 30Dec 35Dec 42


Electronics In The NewsroomRadio Astronomy Pt. 2Electronics In FarmingColumn Loudspeaker DesignHero RobotVoiceprintsClosed CaptioningDbxStarlabInertial NavigationSpy SatellitesHistory Of RadarOutdoor P.A.Saturn Up CloseEqual Tempered ScaleOKLO: Natural NuclearReactorElectronics In Fine ArtTV Stereo SoundA Look At CanteVreleguideBob Stephens And SETIMilitary Communications:Pay TV PrivacyFuses

JanJan

FebFebFebMarMarMarMarAprAprMayJunJunJun

JulJulJulJulAugAugAugSep

Spectrum Wars Sep

Designing Microsystems Pt. I SepDumont: Oscilloscopes AndEarly TV SepAnik C Satellites OctOptical Memories OctCANDU Reactors Oct

13

4313

17

4713

24303513

35

45244276

18

38465731

3958324349

578

3436

The Electronics Revolution Oct 40Rebel Radio Stations Oct 54Designing Microsystems Pt. 2 Oct 62Robotics Nov 18

Fibre Optics Nov 24Military Lasers Nov 40Designing Microsystems Pt. 3 Nov 57

Wheatstone Nov 62Electronic Mail Dec 10

Which Battery To Use Dec 15

Designing Microsystems Pt. 4 Dec 34

Brother EP -20 TypewriterReview Dec 38Nuclear Applications inArcheology Dec 50

Book Review: Math ForElectronics Dec 68

Projects

Sound To Light ModulatorDigital MillivoltmeterSeries 5000 Preamp Pt. 2Styrofoam CutterAudio Spectrum AnalyserSeries 5000 PreampConclusion

Month Page Errata

Jan 28Jan 31

Jan 62Feb 35Feb 52

Feb 68


Are you tired of assembling the kid's Christmas presentsi Frustrated with the incompreliensitAe instructions or total lack thereof? Nowyou can put away all the tools and relax with your brand new edition of Electronics Today complete with the latest index of 1982, '83, and'84 articles and projects. It comes fully assembled and ready to read.. ---------- .

1983Projects Month Page Errata

Dual Logic ProbeDigital Kitchen ScalesSoundtrack GameMultipurpose PC BoardZX Interface BoardLoudspeaker ProtectorGraphic EqualiserDigital Capacitance MeterAudio Analyser Pt. 2Polyphonic Touch OrganTanoverOverload IndicatorProximity DetectorSatellite TV Receiver Pt. I

Revert) AmpAudio OscillatorBomb Drop Sound EffectsDesigning NDFLs60 Watt NDFL'AmplifierAutomatic GreenhouseSprinklerSatellite TV Pt. 2Noise Reduction UnitSignal Line TesterStabilised Power Supply UnitSound SwitchSpectra ColumnPrecision Pulse GeneratorDigital DicePlaymate Pt. I

ZX81 User Defined GraphicsCompressor/LimiterNiCad Charger/RegeneratorExpanded Scale VoltmeterPlaymate Pt. 2

MarMarMarAprAprAprMayMayMayJunJunJunJunJulJulJulJulAugAug

18

255019

465613

326015

32

537313

295364II

17

Aug 54Aug 25Sep 17Sep 30Sep 34Sep 61

OctOctOctNovNovNovDecDecDec

18

2466I012

48202360

Nov 7

Circuit Theory And Components Month Page Errata

Constant Current Generators Jan 21

Josephson Junctions Jan 68Electronic Stores Directory Feb 25Membrane Switches Feb 60VMOS Feb 65Into Digital ICs Pt. 6 Feb 70Superfet Mar 60Into Digital ICs Pt. 7 Mar 63Tone Circuits Apr 27Digital Counters And Timers Apr 30Fault Finding For Beginners Apr 60Into Digital ICs Pt. 8 Apr 65Shockley May 21

Using biFET and biMOS OPAmps May 25Electromusic Techniques Pt. I May 54Into Digital ICs Pt. 9 May 71Instrumentation Techniques Pt. I Jun 29Electromusic Techniques Pt. 2 Jun 57Into Digital Pt. 10 Jun 81

MPU Support Chips Jul 21

Light And Power From DC Jul 24Instrumentation Techniques Pt. 2 Jul 49Into Digital Pt. I I Jul 66Thyristors Aug 22Inside Memory Systems Aug 45Surplus Meters Sep 20CA3059 Zero-Crossin Switch Se 44

1983-19Circuit Theory and Components Month Page Errata

Designing Power Supplies

Tech Tip SpecialSwitched Capacitor Filters Pt. I

Fluke 70 -Series MultimetersSwitched Capacitor Filters Pt. 2Voltage Multipliers

Sep

OctOctNovNovDec

58

2850385245

Computer Month Page Errata

Evaluation Of 14 Computers Jan 24Atari 800 Review Jan 38Smith -Corona TP-1 Review Jan 48ZX8I Revisited Jan 53CP/M For The Apple II Feb 22ZX Interfaces Feb 31

Torch Computer Review Feb 42Zenith Z -I00 Computer Review Mar 43ZX81 Printer Review Mar 46Chess Robot Review Mar 48Northstar Advantage Review Apr 41

Ace, Orange, & SurplustronicsRev. May 39Computing In Britain May 66TRS-80 Model 100 Review Jun 39Introduction To Microcomputers Jun 67Selecting A Computer System Jul 35

Commodore 64 Review Jul 43TRS-80 MCIO Colour Computer Aug 36Low Cost Printer Survey Sep 11

VZ200 Review Sep 24

Improving Your ZX81 Sep 28Spectravideo SV318 Review Oct 20Bulletin Boards Oct 22

Computer Survey Nov 28

Dragon 32 Review Nov 42Introducing Forth Nov 74

50 More Computers Dec 26Sord Socius M5 Review Dec 39

VIC-20 Graphics Listing Dec 64

1984


Induction LoopsAccurate Rise -TimeMeasurementsMicros In AppliancesCOSPAS/SARSATDesigning Microsystems Pt. 5Book Review: CP/M SimplifiedSteinmetzFlying ClocksThe Potent HelixProduct `Review: HitachiVC -6041

ColossusDesigning Microsystems Pt. 6Book Review: MegabucksCellular RadioParticle WeaponsAM StereoBook Review: MicroMaintenanceDesigning Microsystems Pt.7Directional Broadcast Towers

Jan 10

Jan 14

Jan 16

Jan 32Jan 50Jan 62Jan 70Feb 10

Feb 16

Feb 30

Feb 43Feb 46Feb 58Mar 10

Mar 14

Mar 24

Mar 36Mar 48A r 10

1984Features Month Page

Product Review: Logic Trainer Apr 12

Nuclear Wastes Apr 20Steel Tubes and Water Droplets Apr 43Designing MiCrosystems Pt. 8 Apr 54Alexander Graham Bell May 12

Designing Microsystems: Pt. 9 May 28Electronic Maps May 44Computerised Forecasting May 47Genealogy Of The Microchip Jun 9Operation Plowshare Jun 24MachineLanguage Pt. I Jun 62Machine Language Pt. 2 Jul 39VLFs And The Magnetosphere, Jul 60Armstrong Jul 63Alignment By Test Pattern Aug 14

Robotics: Home AndEducational AugMachine Language Pt. 3 AugWhat's Happening In Shortwave SepAM Stereo UpdateHot IceDXing: The Dying HobbyDirect Broadcast SatellitesMachine Code ProgrammingPt. 4Fusion ReactionA Look At VideoMachine Code ProgrammingPt. 5Model Railroad ElectronicsThe ABCs Of TelephonesMachine Code ProgrammingPt. 6BarcodesLaboratories On A ChipElectronic PublishingElectronics In ActionMachine Code ProgrammingPt. 7Digital Watches

SepSepSepSep

Sep

OctOct

OctNovNov

16

4010

18

303334

6212

38

427

24

Nov 30Nov 38Nov 42Nov 46Nov 67

Dec 59Dec 21


ZX8I ADC ConverterParametric EqualiserThe DiggerSupply ProtectorFlash SequencerR/C Substitution BoxMore Pop AmpsStereo SpreaderADC Filter AmplifierFrequency CounterInfinite Probability DetectorThe Light SaverDrum SynthesiserVector GraphicsZener Diode TesterZX Burglar AlarmOP Amp CheckerMultiple Output PortEcho ReverbModem Auto Answer Add-onLow Cost Dwell MeterMotor Controller

JanJan

JanFebFebFebFeb

MarMarMarMarAprAprAprAprMayMayMayJunJunJunJul

203665243240642228385414

18

275218

385214

30 Aug 645318


1984

NAMENom Index 1982-1984 No.

Projects Month Page Errata Circuit Theory and Components Month Page Errata Computer Month Page Errata

Stylus Timer Jul 47 VHSIC Chips May 33 Zorba Review Apr 34Model Railway Switch Optocouplers May 40 Binary Changes May 16

Controller Aug 22 Circuit Supplement Jun 33 Adam Review May 24Servo Interface Aug 58 Coping With Components Pt. I Jun 45 Micro -Professor Ill Review Jun 19

Audio Test Set Sep 19 Principles Of Metal Location Jul 11 ZX8I Programs Jun 42Offbeat Metronome Sep 45 Dec Coping With Components Pt. 2 Jul 26 Sony SMC-70 Review Jul 32Square Wave Oscillator Oct 20 Exar Timer Jul 55 6502 Assembler Utilities Jul 41

Full Wave Rectifier Oct 20 Audio Recording Technology Sep 14 Acorn BBC Review Aug 26Signal Tracer Oct 20 VMOS Circuits Sep 57 Advanced 6502 Programming Aug 42Voltage Follow -and -Hold Oct 21 Getting The Best From Your A Look At The Memotech 512 Aug 50Negative Voltage Generator Oct 22 Scope Oct 10 Applesoft Listings:Microammeter Oct 22 Sample And Hold Circuits Oct 26 Timekeeping Aug 56Eggtimer Oct 24 Thermoelectricity: OTEG PCjr Review Sep 26Dry Cell Charger Oct 52 Devices Nov 27 A Look At ProDOS Sep 55Heads And Tails Game Oct 52 Audio Design Nov 62 EPROMS Oct 44Video Distribution Amplifier Oct 32 More Test Equipment Dec 9 Improving The ZX8I Nov 32Headphone Amplifier Nov 21 Differential Amplifiers Dec 16 Mega -Board Review Nov 36Model Railroad Light Signal Generator Tips Dec 13 ProDOS Booter Nov 70

Controller Nov 55 RS232 Explained Dec 49Computer Month Page ErrataFunction Generator Dec 24 Psion Organiser Review Dec 38

ZX8I Tape Controller Dec 52 Atari 600XL Review Jan 40 SAM Card Review Dec 45Computing Today: Z80 vs 6502 Jan 48 ZX8I Floppy Drive Review Dec 34

Circuit Theory And Components Month Page Errata Columbia 1600 Review Feb 37LM396 Regulator Jan 24 Computing Today: MoreHall Effect Feb 26 Assembler Feb 62Pt. 1 Switching Power Supplies Mar 44 Commodore SX-64 Review Mar 30Zener Diode Primer Apr 40 Computing Today: Hi -ResPt. 2 Switching Power Supplies Apr 48 Circles Mar 64Test Equipment Survey May 8 C-64 Spnte Editor Apr 16

continued from pare 7 For Your Information

Clamp -On AmmeterProviding a large easy to read li-quid crystal display the KYORIT-SU 2001 digital clamp -on ammeterwill provide current measurementsto 1000A. The voltage and currentranges are well protected bydischarge tube, are extinguishingfuse and diode and the withstandvoltage is 3000v. Accurate readingsare possible because of the dualintegral measurement system,while peak hold and data hold areincorporated features. This autoranging clamp -on also providesmeasurements to 750VAc and 2000ohms. The unit weights 500 gramsand comes complete with carryingcase. For more information pleasewrite to: OMINTRONIX LTD.,2410 Dunwin Dr. #4, Mississauga,Ont., L5L 1J9, (416) 828-6221.


Microtel Limited of Burnaby,British Columbia has been award-ed a $1.6 -million contract by theBritish Columbia Hydro & PowerAuthority for analog multiplex,order wire and supervisory equip-ment to be installed along parts ofthe microwave network linking theutility's power grid.

The equipment will be used toupgrade voice and data microwave

26-Mbyte Half -Height Win-chester

Shugart Corp. has expanded itsline of half -height 5.25 -inch Win-chesters with the introduction of a26-Mbyte unit featuring a closed -loop servo system.

In addition to offering highercapacity, the Shugart 724 incor-porates such data protectionfeatures as high -damping four -point shock mounts, a dynamic

service channels at 49 sites mainlybetween the Peace River Dam inB.C.'s far north and Vancouver.

The contract includes the pur-chase of Microtel's 46A3 -SCAnalog Multiplex, 353A OrderWire and PCM (Pulse CodeModulation) Digital Multiplexequipment for intstallation at sitesalong the network.

spindle brake and an actuatorwhich automatically retracts theread/write heads to a dedicatedhead landing/shipping zone whenthe drive is powered down.

The 724, offering 20 Mbytesof formatted capacity, is designedfor desktop computers requiringWinchester performance in a low-cost, compact unit.

For more information on the724 contact Shugart in Markham,Ontario, (416) 475-2655,Circle No. 43 on Reader Service Card.

Centronics Canada Inc. ofMississauga, Ont. has announcedtwo new Long Distance ServiceHot lines for improved customerconvenience.

One Hot Line is linked directlyto Centronics Calgary for servicecentres in B.C. and Alberta, andthe other is linked directly to Cen-tronics Toronto for service centresin Ontario and Hull, Que. Custo-mers in B.C. and Alberta can calltoll free 1-800-661-8129. Custo-mers in Ontario and Hull, Que.,can telephone 1-800-268-0432.Calgary and Toronto clients maycontinue to contact their servicecentres directly at the localnumber.

Control Data Canada, Ltd. has an-nounced the establishment of theWomen's Training Centre to trainfemale students in computercareer -entry skills.

The Centre will be part of thecompany's Toronto Control DataInstitute and will offer courses inskills required to operate in anautomated office environment. Inaddition, courses in computer pro-gramming, computer operationsand computer maintenance andrepair will be available. Thecourses will be offered at ControlData's 20 Hallcrown Place officesin Willowdale Ontario. For moreinfomation call (416) 826-8640.


Special Offer OnBack Issues!For a limited time, Moorshead Publications is offering available back issues for$2.00 each. Complete your collection of Electronics Today now. Fill out the coupon and mailwith your payment today. This offer expires February 28, 1985. See the order form on page 43 for acomplete list of the available back issues. Also see the issue by issue index on pages 16, 17 and 18for Editorial content of issues.

14,

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Series

Designer's Notebook:

Fig. I Metal tracks laid out on aULA, as seen on a VDU duringdesign. The filled -in white area aremetal tracks, the thin white linesoutline transistors and diffusedcross-unders, while the fain greylines mark allowed trackplacements.

Customised ICs are catching on as fast ascustomised license plates. An explanation on how

PLAs and ULAs have brought down the price.

IN THE PAST ten years or so the com-plexity and density of circuits integratedonto one chip has increased dramatically.This trend is continuing for the followingreasons:

Size: usually, one chip is smaller thantwenty. Smaller circuits fit into smallerboxes, which are cheaper to manufactureand transport than large heavy ones. Ifseveral PCBs can become one, inter -PCBconnections are saved.

Power consumption: in general a singledevice consumes less power than several.The consequent drop in heat dissipationmay allow natural instead of fan -assistedcooling, or reduction of heatsink sizes, orboth. Also a less bulky power supply isneeded. The whole equipment may thenreduce in size and weight by far more thanthe initial amount caused directly by in-tegration.

Speed: devices on large scale ICs tend tobe smaller than those in medium or small-scale ICs. The switching speed of smalldevices is usually faster than that of largedevices, so the single chip is faster thanseveral.

Reliability: one chip is more reliable thanseveral. Reducing the chip count in equip-ment reduces the number of interconnec-tions and hence the probability of a faulty20

By S.M. Smith

connection. More reliable equipmentmeans cheaper equipment, as less moneyhas to be allocated for fixing faults arisingduring and after production.

Security: a board full of TTL ICs is easilycopied by unscrupulous competitors. Ananonymous black plastic block can onlybe copied with a lot of effort.

There are several ways of putting alogic system on a chip, ranging from thefull custom IC down to the familiarPROM. A fully custom integrated circuitis a complicated device that takes monthsto design and develop, and requiresmassive investment in plant to manufac-ture. To recoup the cost of this requiressales of either a huge number of devices atreasonable prices, or a few sales atridiculous prices, the latter being luxuryindulged in only by the aerospace anddefence industries. To understand why anIC costs so much to develop, it isnecessary first of all to have an idea of themanufacturing process.

Integrated circuits are fabricated onthin sheets of silicon 2" to 5" in diameter,called wafers. The silicon used for ICfabrication has to be extremely pure -99.99999% pure. It must also be mon-crystalline, with the atoms laid out in aregular three-dimensional pattern and nodefects. Since the wafer is polycrystalline

silicon, a near -perfect layer of single -crystal silicon must be grown on the wafersurface, using a process called epitaxy.

Making TransistorsTransistors and resistors are made by dop-ing the silicon with minute quantities ofother elements, such as boron, gold,phosphor and indium. Obviously, a singletransistor 3" in diameter is of little use, sothe doping is introduced only to selectedareas of the silicon surface. Areas to bedoped are defined by holes in a layer ofsilicon dioxide on the wafer; the oxideprevents dopant reaching the silicon.

The shape and location of the holesin the oxide layer are ultimately determin-ed by a pattern held in a computer. Thispattern is converted into a 400 X full sizemaster print which is photographicallyreduced in two or three stages onto achrome -coated glass plate, the 'mask'.Several hundred patterns are repeatedacross the mask in a precise regular array,so one wafer will yield several hundredchips (see Fig. 1).

The wafer is coated with a photo -resistive polymer, which reacts to ultra-violet light (a similar process is used inPCB production). The mask is then plac-ed over the wafer, in precise alignmentwith previous processing steps, and thenthe wafer is exposed to UV. The mask is


removed and the unexposed resist is rinsedoff with a solvent - the exposed resist,hardened under the ultraviolet, does notrinse away. Now the un-covered section ofthe oxide can be etched away with acid,leaving silicon exposed for doping.

The final mask defines the metallisa-tion layer, which is a thin network ofaluminium tracks interconnecting deviceson the chip. There may be several metallayers, separated by insulating oxidelayers.

There are around seven processingstages for each mask, and an IC designmay require 5 to 12 masks. this makes theprocess long, expensive and error -prone.

The Expertise GapThere are few engineers capable of design-ing an integrated circuit at this level ofcomplexity, with control over dopinglevels, transistor sizes and so on. For-tunately, many applications do not re-quire minute control over the electricalcharateristics of the devices on the chip.Semi -custom logic design allows an or-dinary logic designer to design an in-tegrated circuit.

The most complex semi -custom ap-proach is the standard cell. Here thedesigner has access to a computerdatabase containing mask layouts foroften -used devices and functions up to thecomplexity of, perhaps, a full adder. Thedesigner extracts from the database thedevices and functions needed; he or shemay have some control over electrical per-formance if layouts are held for differentversions of the same device.

This is still an expensive method;although design data has been previouslycalculated for each function required, newmasks have to be made for each IC. To becost effective, large returns on sales mustbe certain. The advantage over fullcustom is the lower expertise required ofthe designer and faster design time, withonly a small loss in performance.

Uncommitted LogicThe next level down in terms of cost/timeis the gate array, or uncommitted logic ar-ray (ULA), to which the bulk of this arti-cle is devoted. In the ULA the devices andsome inbuilt interconnection are ready -fabricated. The devices are laid out in aregular array with channels betweengroups of devices for interconnectionrouting (Fig. 1). The designer's job is tocomplete the interconnection by specify-ing a metallisation mask layout.

Although the designer has no controlover electrical performance of the devices,and some waste of silicon area is in-evitable due to the fixed form of the ar-ray, the ULA is attractive because of itsfast design time (5 to 12 weeks) and lowerproduction costs (only one or possiblythree new masks have to be produced). ItElectronics Today January 1985

is therefore suitable for projects expectingrelatively low sales volume.

Fuse ProgrammingNext comes the fuse -programmable logicarray (FPLA; some versions are calledPAL or PLA). These come in a number ofdifferent versions, but basically consist ofa set of AND gates feeding on a set of ORgates. Fusible links control which of thechip inputs go to which AND input, andwhich AND output to which OR input.Some FPLA's incorporate D -types,registers and optional feedback loops toallow sequential circuits to be burnt in.

FPLAs have the advantage of veryfast design time (a few minutes fromspecification of the logic function to pro-duction of the program for blowing thearray). They tend to lack versatility com-pared with a ULA and make inefficientuse of silicon. They have the advantage ofinhouse programming (no need to sendthem away to the manufacturer, with theattendant delays) and can be very cost-effective in some applications.

And PROMs Too!The final option is to use the PROM (Pro-grammable Read Only Memory). This hasthe advantage again of on -the -spot pro-gramming and may implement more com-plex logic functions than the FPLA. Therequired truth -table is programmed intothe PROM; the address lines are used asthe logical inputs, and the data lines arethe required outputs. However, thePROM is a comparatively slow device,and its use may often be a waste of silicon;as an extreme example, an octal inverter(16 transistors in CMOS) implemented ona PROM requires 256 words by 8 bits -a 2K memory!

Because of the reasons above, theULA is the most important of the routesto a semi -custom logic IC at present. It islikely to become more so in the future asthe pace of technology quickens, deman-ding new designs in shorter timescales,and as the software tools for ULA designimprove, allowing more fully automateddesign and design of larger chips.

CMOS is the fastest -growing gate ar-ray technology at the moment, due to it'scombination of speed, power and con-sumption, packing density and ease ofdesign.

Designing A ULAIt would be almost impossible to design aULA without the help of a computer.People are slow, they find checking bor-ing and they make mistakes. Fortunately,computers are not yet intelligent enoughto get bored.

The design starts, usually, with a`breadboard' model of the circuit, in TTLor CMOS or whatever is the mostsuitable. This stage is used to check if theideas are correct; it may be considered un-necessary if a well-known design is beingimplemented. The design is thentranslated into a form suitable for puttingon a ULA. There will be some differencesbetween the breadboard and ULA versionof the circuit because in CMOS arrayssome logic structures are more easily im-plemented than in bipolar technology or4000 -series CMOS.

One basic unit, fundamental toCMOS gate array design, is the transmis-sion gate, a pair of P and N channel tran-sistors with their sources and drains tiedtogether, with complementary gatesignals, Fig. 2. When CONTROL is highthe N -channel transistor is turned on, andsince CONTROL is low, the P -channeltransistor is turned on too. Thus a signalcan pass from A to B.

CONTROL

1. SUBSTRATETO SUPPLY

SUBSTRATETTO GROUND

CONTROL

CIRCUIT

CONTROL

(THE PRESENCE OFCONTROL IS ASSUMED)

SYMBOL

Fig. 2 The transmission gate.

Using this construct, a D -type flip-flop, for instance can be made with just 16transistors, Fig. 3. An even economicalD -type can be implemented using only

CK

CK

CK

CK

0 CI

>1oo

Fig. 3 D -type flip-flop (positive edge triggered) using 16 tranisistors (two per transmission gate, twoper inverter - circuit not shown for inverter, but assumed very simple)

continued on page 53 21

Project

A simple, low-costcapacitance meter forthe test bench.

By John Linsley Hood

ONE of the simplest ways of measuringcapacitance is to connect the componentunder test to a suitable (low voltage)source of AC, and then measure the cur-rent which flows through it. For smallvalues of capacitance, this is obviously notgoing to be very big, so some kind of elec-tronic amplifier will be needed.

A suitable arrangement is shown inoutline form in Fig. 1. The only specificrequirement is that Rx must be very smallin value in comparison with the im-pedance of the capacitor under test.

The CircuitThe actual circuit used in the instrument isshown in Fig. 2, and is simply a high inputimpedance milli -voltmeter having a FSDinput sensitivity of about 27mV and builtaround a TL071 op -amp.

The range switch is chosen to give fullscale capacitance value indications of10pF to 100uF. The capacitance ranges in-crement in steps of 1:10:100, etc, using thegiven values for R1 -R9, but there is noreason why the constructor should notadopt a 1:3:10:30 series by making theresistor bank have values in the 3M3,IMO, 330K, 100K . . sequence.

For testing electrolytics, it is desirablethat there is a small polarising voltage onthe capacitor under test. This is done byswitching the lower end of the resistorbank of SW1 to the -5V line. This effec-tively puts the DC supply smoothingcapacitor of this line in series with thecapacitor under test, so it is advisable tomake these large with respect to the 100uFmaximum instrument range.

Fig. 1 A simple method of measuringcapacitance.

AnalogCapacitanceMeterConstructionVirtually all of the low -voltage circuitry ismounted on the PCB, including the meterand the range -setting switch with itsassociated resistors. However, neither thetransformer nor the fuse are mounted onthe board because of the risk of AC pick-up from them.

Assembling the PCB shouldn't pre-sent any problems provided the overlay isfollowed carefully. Begin by solderingSW1 into place and then move on to theresistors and capacitors, taking care withC2, 3 and 4 which are electrolytic andmust be inserted the right way around.Finally install the diodes and the op -amp,again taking note of polarity. The op -ampis a bi-FET device and requires no specialhandling precautions; some constructorsmay prefer to use a socket for it but this isnot essential.

Because of the susceptibility of thehigh impedance input to AC pick-up, it isrecommended that the instrument behoused in a die-cast box. No particulartype is specified, but you should chooseone which is large enough to accom-modate the PCB plus the off -board con-trols and which has sufficient depth toallow the transformer to be placed wellaway from sensitive parts of the circuit.

The test terminals should be position-ed close to the appropriate pads on thePCB and then connected up using veryshort lengths of wire. These two leadsshould not, of course, be twisted togethersince this would introduce a certainamount of capacitance and thus affect theaccuracy of the unit. SW2 presents no'such problems and can be wired up in thenormal way.

.-a0/C

0

10p

R1560k

V`R2

100pR333k

10n

R43k3

1n0

Cl

-100n

m -AAA" --0R5

100u02

IC

4330R

1u0100n

33R R10

R9100R-d\AA/,

R7 3M33R3 RV1

470R--"VVVN

R8 +C2OR33 NORMAL 100u

SW20

CAPACITORUNDER TEST

C3+4700u

BV

POLARISED

+C44700u

N L0 0

NOTE:IC1 TL071D1-4 1N41477

FS1 50mA FUSEFS2 1A FUSE

SW3b

FS2

Fig. 2 Circuit diagram of the direct -reading capacitance meter.


SW2 "NON -POLARISED'

CAPACITORSW2 'POLARISED' UNDER TEST

CT Ti)I

3V(T11

C4

C3

I

3V(T1)

CAPACITORUNDER TEST

SW2 (POLE/

R5 R4

Fig. 3 Component overlay of the PCB.

PARTS LISTResistorsRI 560kR2 IMOR3 33kR4 3k3R5 330RR6 33RR7 3R3R8 R33R9 3M3R10 100RRV1 470R

CapacitorsCI 100nC2 IOOu 16V

electrolyticC3,4 4700u 6v

electrolyticSemiconductorsICI TL071DI -4 1 N4148BR I W005

MiscellaneousMI IOOu moving coil

meterSW1 I pole 8 way rotary switchSW2 SPDT toggle switchSW3 DPDT mains toggle switchTl 3-0-3V 3VA chassis mounting

transformerFl 50mA 20mm fuse and chassis

mounting holderF2 loudspeaker -type twin spring

terminals

PCB; diecast box; mains cable and strainrelief bush; knob for SW1; spacers, nutsand bolts for mounting PCB and TI;screening material.

The transformer, power switch andfuse should all be positioned well awayfrom the op -amp and the test terminals,particularly the terminal which connectsto the wiper of SW1 since this point is athigh impedance and therefore very sen-sitive to AC pick-up. The leads from thesecondary of the transformer to the PCBshould be tightly twisted together sincethis will reduce the magnetic field aroundthem and hence the risk of pick-up. It mayalso be necessary to screen the op -ampand the high impedance terminal com-pletely if the meter is to operate correctlyon its two most sensitive ranges.

Setting up the instrument, on com-pletion, requires the availability of a fewgood quality capacitors of which thecapacitance is known to an adequatedegree of accuracy. The value of RV1 canthen be adjusted to give the best fit overseveral ranges.

It is possible to attach a pair of leadsto the test terminals and use them to testcapacitors in situ, but AC pick-up on thehigh impedance lead will introduce errorsand this method can therefore only be us-ed with large values of capacitance. In allother circumstances it is advisable to placethe capacitor under test directly across thetest terminals. If the size or constructionof a capacitor prevents its being connectedin this way, attach a flying lead to the lowimpedance test terminal (the one from thesecondary of the transformer) and use thisto connect one side of the capacitor whilethe other side is inserted directly into thehigh impedance terminal.

2jElectronics Today January 8985 23

Review

Autodial your computerinto a telecom networkand download at 1200baud with the EMP1200A.

By £ Penn

WORKING computer bulletin boardswith a 300 baud modem isn't all that bad,dig, cause you can only read so fast, youknow? It's helpful to let the text dribblepast when your eyes are little red slits.When you come to download good stufflike free software, though, it's Snail City:"Download Time: Come Back Next Week-end".

So, naturally we need something hi -techto free up more leisure time for us, and 1200baud is the answer, providing, of course,that we can get back to 300 anytime forleaving strange messages on our favouriteBBS.

Now, there are terminal programs andautodialers and various modems happen-ing, but who really needs all that? What ifyou could get it all in one box? What if,indeed. The very box exists. It is called theEMP 1200A, from the good people whobrought you the EMP MMI01 Mini -Modem. It consists of a, ah, box. On thefront of the box are red LEDs and threebuttons. On the back is an RS232 con-nector, an 8 -lever switch, a telephone jackand a cord that goes to your phone jack.The whole thing gets lit up by a 12 VACplug pack.

Setting UpIn the next world, you won't have to. 32 -bit CPUs will fathom what's happeningand adjust accordingly. In this life, yerbeat. You'll have to - aggh! - read theinstructions. You'll find that this modemhas pretty much what you need: 300/1200baud selectable from the front panel, rearswitch selection of parameters such asnumber of bits, and self -test. It has auto -dialing and automatic disconnect. It hasauto or manual answer and originate. Whatmore could you ask? You could ask for amanual which explains all these things, iswhat you could ask for, but you don't getone. However, if you follow all the advice24

EMP 1200A Modem

in the little booklet ("Press switch 1 downand leave switch 2 up") everything willwork and the LEDs will flash satisfyingly,even if their functions aren't explained.

And how does all this blend with themany wires of your computer? With anRS232 output and cable. Without you don'tgot no RS232, you don't get no telecom.Help is at hand, adapters are available, seeyour friendly neighbourhood computerdealer.

Using ItActivate your RS232 output by perform-ing the necessary voodoo required by,your computer. Be sure the modem is plu-gged into the wall and your telephone plu-gged into the modem. All set? Here wego.

The phone will ring. It will be yourmother-in-law asking why the line isalways busy. She will talk for three hours.Tell her the house has just caught fire andhang up. Check the computer screen for aright -arrow symbol; this symbolizespeace and harmony between the computerand the modem. Type "D" and thenumber you wish to call, including areacodes if you like. A tiny relay will chatterinside the modem. If the number isn'tanswered within 30 seconds, the word"disconnect" will appear on the screen.You can then change numbers, or elsetype "R" for redialing. It's not quite asslick as having it all done for yourobotically with auto -recall, but it beatswearing out your fingers on a rotary dial.

For working the digital conversationthe other way, just leave it to the modem.

When the phone rings, the "RI" LEDwill light and the modem answers. If itdetects a carrier, it will begin receivingafter automatically figuring out the properbaud rate. If it detects your mother-in-law, it hangs up. If it loses the carrier, italso hangs up.

OtherThere are various testing modes availableto verify that everything is getting alongwith everything else before you place thatcall to Hawaii. The "Loopback" mode,for instance, is selected from the rearswitch, and takes in any data transmittedby the terminal (your computer) and sendsit back to the computer for verification.

During me strolls through variousBBSs at both 300 and 1200 baud, the EMPperformed flawlessly as a good boxshould. The built-in dialer saves having tohave a terminal program in software; onlyan RS232 port is required. Very flexible,very nice, and when you can't think ofanything else to write, quote specs, I

always say.

Modes:300 or 1200 baudType: Full duplexDialer: keyboard controlled, 10 ppsInterface: RS232Phone Interface: Modular jacksRegular Price: $539.00The EMP 1200A is available from:Mark Gee Enterprises Ltd.,1990 Ellesmere Rd., Unit 9,Scarborough, Ont. MIH 2 W2(416) 431-4417

Circle No. 52 on Reader Service Card.


Train for the Fastest Growing Job Skill in North America

Only NRI teaches you to service andrepair all computers as you buildyour own 16 -bit IBM-compatiblemicro

As computers move intooffices and homes by the millions,the demand for trained computerservice technicians surges forward.The Department of Labor estimatesthat computer service jobs will actuallydouble in the next ten years-a fastergrowth than any other occupation.

7btal System TrainingAs an NRI student, you'll get total

hands-on training as you actually build yourown Sanyo MBC-550-2 computer from thekeyboard up. Only a person who knows allthe underlying fundamentals can cope withall the significant brands of computers. Andas an NRI graduate, you'll possess the up-to-the-minute combination of theory andpractical experience that will lead you tosuccess on the job.

You learn at your own convenience, inyour own home, at your own comfortablepace. Without classroom pressures, withoutrigid night -school schedules,without wasted time. Your ownpersonal NR1 instructor and NRI'scomplete technical staff willanswer your questions, give youguidance and special helpwhenever you may need it.

The Exciting SanyoMBC-550-2-YoursTo Keep

Critics hail the new Sanyo asthe "most intriguing" of all theIBM-PC compatible computers. It uses thesame 8088 microprocessor as the IBM-PCand the MS/DOS operating system. So, you'llbe able to choose thousands of off -the -shelfsoftware programs to run on your completedSanyo.

As you build the Sanyo from thekeyboard up, you'll perform demonstiationsand experiments that will give you a totalmastery of computer operations andservicing techniques. You'll do programmingin BASIC language. You'll prepare interfacesfor peripherals such as printers and joysticks.Using utility programs, you'll check out 8088functioning. NRI's easy step-by-stepdirections will guide you all the way rightinto one of today's fastest growing fields as acomputer service technician. And the entire

system, including allthe bundled softwareand extensive datamanuals, is yours tokeep as part of yourtraining.

100 -Page FreeCatalog TellsMore

NRI is the only homestudy school thattrains you as youassemble a top -brand micro-computer. Afterbuilding your ownlogic probe, you'llassemble the"intelligent"keyboard...

then installthe computerpower supply,checking all thecircuits andconnections withNRI's DigitalMultimeter. Fromthere you'll moveon to install thedisk drive andmonitor.

Send the postage -paid reply card todayfor NRI's big 100 -page color catalog, whichgives you all the facts about NRI training inMicrocomputers, Robotics, Data Com-munications, TV/Video/Audio Servicing,and other growing high-tech career fields.If the card is missing write to NR1 at theaddress below.

Your NRI Course Includesa Sanyo MBC-550-2 Computerwith 128K RAM, Monitor, Disk Drive,and "Intelligent" Keyboard; The NRIDiscovery Lab', Teaching Circuit Design andOperations; a Digital Multimeter; BundledSpread Sheet and Word Processing SoftwareWorth $1500 at Retail-and More.

ArAPArscHooLsMcGraw-Hill Continuing Education Center330 Progress AvenueScarborough, Ontario MIP 2Z5or telephone 416-293-8787

We'll give you tomorrow.IBM is a Registered Trademark of InternationalBusiness Machine Corporation.

MISdmi

Plasmons:ResearchResearch into high -efficiency solar cellscould change the ap-proach to solar energyconversion; efficienciesas high as 50 percentmay be possible.

By David DempsterHAVE you ever heard of a surface plas-mon? If the basic research in solar celltechnology now being conducted atNASA's Lewis Research Centre inCleveland is successful, surface plasmonscould become a household word in theenergy lexicon of the future. Surface plas-mon research is one of several fronts onwhich the centre is seeking to advance thestate-of-the-art of systems to provideelectric power in space.

Solar cells are devices that produceelectric current when exposed to sunlight,and the most advanced field of solar cellinvestigation at Lewis today involves theproduction of electricity without the useof semiconductor material.

The surface plasmon cell representssuch an approach, and some day it couldachieve very high levels of efficiency. Itcaptures the energy in a broad spectrum oflightwaves as they strike a rough metallicsurface, are converted into high speedplasma waves and are then collected andconverted into power. Efficiency near 50percent may be feasible, according toAmerico F. Forestieri, head of Lewis'Photovoltaic Technology Section. (Thiscontrasts with less than 10 percent for con-ventional cells.)

"We are just beginning to makedevices that show the feasibility of thevarious aspects of this totally new energyconversion technique," Forestieri said."The challenge will be to incorporate allaspects into one practical device. By theearly 1990's we hope to have accom-plished the goal.

"All of our solar cell technology workcurrently is focused on space uses," saidForestieri, "but the efficiency and othergains from these efforts will lead toimprovements in solar cells designed forterrestrial purposes as well.

"For example, if we can increase theefficiency of solar cells by, say, a factorof three, this would substantially reducethe area of an array and also reduce the26

Solar Cell

balance of systems cost for photovoltaicsystems. By doing that, photovoltaic sys-tems could then be competitive with otherpower sources such as the utilities."

Uses in SpaceA large United States space station,

orbiting the earth and requiring highpower levels, may benefit from suchimproved technology, but near -termapplication possibilities include moresophisticated satellites for communica-tions, weather forecasting, reconnais-sance of earth resources and similarservices.

One of the most promising near -termsemiconductor approaches to improvedpower generation systems for spaceinvolves the gallium aresenide solar cell.When perfected, this cell, made by mix-ing gallium and arsenic or so-called III -Vcompounds, would equip builders ofspacecraft with a more efficient solar cellarray able to convert 18 percent of theenergy it receives from the sun into elec-tricity. Future efficiency may be as highas 22 percent.

Dr. Irving Weinberg, scientific consul-tant in photovoltaics at Lewis, ticks offsome basic advantages: "Gallium arse -


nide cells lose power under extreme heatat only half the rate of the tried and truesilicon cells, are less susceptible to spaceradiation damage, can recover theirenergy -producing potential after radia-tion at a much lower 'healing' tem-perature than silicon, and can be thinnerand hence lighter than a typical siliconcell.

"Added to these benefits is the cell'sability to be used under concentrated sun-light, and we hope to exploit this to pro-duce greater amounts of power at a lowerunit cost from a smaller area of cells."

"One example is a gallium arsenidecell only a fraction of the size of a siliconcell that can be placed at the focal point ofa small 5 centimeter (2 inch) diameterCassegrainian mirror concentrator. TheCassegrainian mirror concentrator col-lects and focuses 100 times more light perunit area on the cell to produce largeramounts of power. Because cell effi-ciency increases with sunlight intensity,more power can be produced from a givenarea of cells. This permits the use ofsmaller arrays. Temperatures on the cellin the concentrator remain remarkablylow and long life can be expected."

Lewis is already producing some of thenew gallium arsenide cells for experimen-tal purposes. The ultimate goal is to makean ultrathin gallium arsenide cell that willbe more efficient and radiation resistantthan present silicon cells and comparablein price.

The Cascade CellForestieri and his staff are also workingon what they call the ultimate semicon-ductor solar cell: the Cascade cell. Thisdiffers from any others in that it can gen-erate maximum power from each of thecolours that compose "white sunlight."

Other cells composed of only one semi-conducting substance generate peak per-formance at one wavelength or colouronly. The Cascade cell will employ layersof semiconductors that each produce peakpower from a preferred colour of light. Aslight cascades through each layer, onecolour is filtered out to generate powerand the others are passed through to beused by the layers below.

Lewis researchers are using a vapourdeposition process that can lay down achemical film a fraction the thickness of ahuman hair across a substrate to build theCascade cell. The total Cascade layercake is about half the thickness of ahuman hair.

"The Cascade cell should achieve effi-ciencies up to 30 percent and enable us toreduce the size and weight of structuresrequired to hold solar cell arrays," saidForestieri. "That will be a big advantagein space where smaller solar wings willreduce weight and permit greater payloadaboard spacecraft. It will also be ofElectronics Today January 1985

advantage to builders of terrestrialunits."

Welding the CellsAnother area of study at Lewis is todevelop a practical welding technique forsolar cell arrays to replace the use of sol-der in wiring the cells together to providepractical voltage and current levels.Intense heat, like that encountered byplanetary probes sent into the near -sunenvironment, would melt the solder con-nections, causing a loss of power.

Temperature cycles of intense heat andcold as encountered by satellites movingfrom the sun side of a planet to the darkside may cause solder to become brittleand eventually break. A welded array thatwill be able to withstand greater tem-perature extremes and cycles is a goal ofLewis scientists.

4110251QyarAcINTERNATIONAL LTD.

(416) 298.3280Telex 065-26150

Service Centre and Retail Outlet. 4051 Sheppard Ave., East, Agincourt, Ontario M 1S 1S8

Japanese Parts SpecialistsPARTS 100% GUARANTEED

1985 Prices

4116 150nS NEC or MIT $ 1.654116 20ONS Ceramic $ 1.354164 15ONS MIT $ 5.752716 2Kx8 HITACHI, NEC $ 4.992732A 4Kx8 T1 $ 8.502732 NEC $ 6.992764 8Kx8Mitsubishi 250NS $ 9.8527128 30ONS Hitachi $20.952532 Hitachi $ 7.252114 200NS (Hitachi) $ 2.252128-2, 2116, 4016, 2016 $ 8.006116P 15ONS Hitachi $ 7.75TMS 4416 12ONS 4Kx16 $ 9.50HM 6264 LP -15 $CALL41256 TMM or NEC $CALL

CPUZ80A NEC $ 5.756502A 2MHz $ 6 996502 $ 6.506845 CRT Controller (Hitachi)1 Mhz $10.996522 $ 6.996850 $ 4.998035 $11.008039 $12.508279 $ 9.008155 $11.508085A $12.508086 $19.95UPD 7220D $59.95

800 Series for IBMa) 8088D NECb) 8237A-5 NECc) 8253A-5d) 8259A-2e) 8255A-5f) 8284Ag) 8288Dh) UPD 765Ai) 82C43Cj) 82C53-5k) 8243C1)8257

$21.50$19.95$ 9.00$ 9.00$11.99$10.99$18.50$28.50$11.00$10.75$12.00$12.00

SPECIALSDisk Drive (Super Sale)IBM CompatiblePanasonic JA551-2 (same as ShugartSA455) $235.00

Apple CompatiblePanasonic JA550-2 $249.00ASUKA NF 555 $239.00MITAC (Shugart SA390) $215.00

PrinterRoland $369.00Mannesman Tally $410.00

MonitorGreen $129.00Amber $139.00

5-1/4 Floppy Disk Case (storage up to150 diskettes) Lock included $ 29.955A Hydro approved Switching PowerSupply (for Apple) $ 85.0015A, 130W Switching Power Supply forIBM PCB's $169.0052 function numeric keyboard (electronictouch) upper/lower case) $ 99.001. Colour R.F. Modulator $ 15.00

Apple Compatible Peripheralsa) 128K RAM Card $185.00b) 16K RAM Card $ 49.00c) 80 Column Card $ 69.00d) Disk Controller Card $ 49.00e) Z80 Card $ 60.00f) Communication Card $ 79.00g) 40/80 Col. soft switch $$19.95

Check our low price TTL, 74LS Series"Price as low as 55"Example: 74LS00 55c

Mail Orders: Send a certified cheque ormoney order plus $4.00 for shipping andhandling. For Special Delivery, please add$1.00 extra. Ontario residents add 7% P.S.T.Visa & Master card accepted.


COPPUTER

INC.

Toll Free Orders Only

1.800-387-1385Order Checking (416)925-8291Technical Data (416)925-1105

FIRMWARE FOR BARE WIRED APPLEPCB's PERIPHERALSCLOCK DISK $ 8.00 16K $45.00MUSIC 2 DISKS . $15.00 DISK $45.00128K 3 DISKS $20.00 Z-80 $45.00WILD DISK $ 8.00 80 COLUMN $65.00SAM DISK $ 8.00 80 COL SS $70.00SPRITE DISK $ 8.00 13/16 SHAMROCK $55.00

n n nri 17 Ili 111 ri i IN i --1 LI I I LLI I\ 1-

316 College St.Toronto, Ontario M5T 1S3

GRAPLER EPROM .$ 8.00 128K NO ICS $34.95

APPLE® ITEMS NEW LOW BARE 80 COL 3 EPROMS .$20.00 128K Zero K80 COLSS 3 EPROMS 128K 64K

$55.00$99.00

PCB PRICES * 8.00 SSM MODEM$150.00

SSM EPROM $$20.00 128K 128K

$150.00(A) SOLID ABS NUMERIC CASE MULTIFUNC EPROM APPLACARD $150.00Fits our function KB just right $59.95 As you know the Apple bare pcb business is fading $ 8.00(B) NUMERIC FUNCTION KEYBOARD away. We have decided to clear out the rest of our Apple DISK 2 PROMS $15.0088 Basic & CPM functions $89.95 bare pcb at discount prices until they are all gone. SHAMROCK DISK PROMSShorter type, non numeric $79.95 FIRST COME: FIRST SERVED, MINIMUM 5 CARDS $15.00(C) 6502 MOTHER BOARD 48K RS232 2 PROMS .$15.00Our famous + with prototype area $29.95 GROUP 1 WILD EPROM $ 8.00(D) BLACK BEAUTY POWER SUPPLY (A) REAL TIME CLOCKNow CSA° approved to protect you $79.95 (B) RANA 4 DRIVE(E) SYSTEM SAVIOUR FAN & OUTLETS (C) 9 VOICE MUSIC

,totoThe famous low cost fan/surge sup $45.00 (D) BUFFER PRINTER(F) GREAT DEAL STILL GOING STRONG (E) DISC CONTROLLERA,D,C,D above and any 4 bare PCB $249.00 (F) SHAMROCK DISC II ALL(G) IBM° CASE FOR 6502 PCB2 drives, mother PCB, PS fit in $69.95

(G) PIA $7.00 EACH(H) EPROM vep 46

.,

(I) WILD CARD EPROM(.1) SAM(K) RS232 PRINTER PROGRAMMER/

HARD TO GET PARTS (L) RS232 MODEM (COM) ERASERThe VEP-46 programmer programs 16K to 128K EPROMS

8 POS DIP SWITCH $2.50 MPSA13 $0.50 GROUP 2 four at a time, with each bit programmable via the hostDISK MALE PCB 2N2904 $0.20 GRAPPLER computer. Will also erase up to 10 EPROMS at a time.CON $1.50 2N3906 $0.30

(M)80 COLUMN Ideal for small production runs or EPROM development

DISK FEM FLAT CON. 2N2222 $0.35(N)(0) 80 COLUMN SOFT SW ALL work. Specify Apple or IBM host adaptor $449.00

$1.50 2N2907 $0.40 (FI) Z-80 CRYSTALS6 PIN INLINE POWER MPSU51 $1.00 (0) RGB $9.00 EACH

$1.00 2N4258 $0.75 (R) SPRITE GRAPHICS 1.00 MHZ $4.95 6.144 MHZ $3.956 PIN SQUARE POWER 1K,9 PIN SIP $1.00 1.8432 MHZ $3.99 8.000 MHZ $2.95

$1.00 1K, 8 PIN SIP $1.00 2.000 MHZ $3.99 10.00 MHZ $2.95RCA JACK PCB $0.75 10K, 10 PIN SIP $1.00 GROUP 3

AUDIO JACK PCB ....$0.50 4 POS DIP SWITCH (S) SSM MODEM 4.000 MHZ $2.99 14.318 MHZ $2.49

50 Pf TRIMCAP $1.00 $1.50 (T) APPLE MULTIFUNCTION 3.579 MHZ SMALL...$2.99 16.00 MHZ $2.95220 Ohm TRIMPOT ..$0.50 (U) APPLACARD ALL 3,579 MHZ LARGE . .$1.49 17.43 MHZ $2.9568A45 $10.00 (VV) APPARAT EPROM PROG $11.00 EACH 4.032 MHZ $3.99 18.00 MHZ $2.95MC3242 $10.00 (X) 16K

6.000 MHZ $3.95 18.432 MHZ $2.95 Prices so low we require payment with order.


continued from page 18 For Your Information

New Office Software forApples and FranklinsThe Magic Office System by Artsciis a giant step ahead. The power,simplicity and ease -of -use of win-dowing technology is nowavailable for Apple Ile, Ilc andFranklin users. The Magic OfficeSystem combines: A greatly enhanced version ofMagic Window II, the popular"see what you get" word pro-cessor An electronic spreadsheet fasterand more powerful than Visicalc,with variable width columns andoutput formatting A business graphics package forpie charts and multiple bar graphs. An automatic spelling checker

Also of note: Lisa -type filefolders & documents; on -screen

text justificiation; menu & func-tion key driven; single keycopy/back-up; restores originalfile from disk; does Mail Mergeand supports many printers and in-terfaces. In comparison Ap-pleWorks, a similar integratedsoftware package from AppleComputer Inc. is not capable ofany of these functions. The entireprogram is on one disk and eachprogram is fully integrated withthe other.

The Magic Office System isdistributed by MicronDistributing, 409 Queen StreetWest, Toronto, Ontario1-800-268-9052/ (416) 593-9862and is available at your local com-puter store. Suggested retail is$399.95.


IC LotionLotion for your chapped chips?Not yet. R&R Lotion, of 1220North Statem, Tempe, Arizona85281, are offering a hand lotionfor those in the printed circuitrepair or manufacturing trades. Ifyou work with solvents and use ahand lotion to prevent sandpaperskin, chance are you're gettingsilicone, lanolin, or mineral oil onany PCBs that you handle. Solderflux can't be relied on to remove

these contaminants. R&R's lotionis said to contain no contaminantsthat would affect solderability orcause corrosion. You can contactthem at the above address, or call(602) 968-7787.


Servo -amp

Servo -Amplifiers Inc. has an-nounced a new and more powerfuladdition to its line of digital inter-faced DC motor speed controls.This new Model 14-25A is for com-puter controlled DC motor ap-plicatioes, providing up to 3000watts of true servo power. Thecomputer user is able to attach astandard 90 Volt DC motorthrough the Model 14-25A to aparallel port without causing anyelectrical interference in the

microprocessor. This outstandingfeature is achieved through the useof opto-isolators. A further costand space saving advantage of theModel 14-25A is the ability to at-tach it directly to a 110 Volt linewithout expensive use of powersupply or transformers. Contact:Servo -Amplifiers Inc., 2 Bloor St.W., Suite 100-265, Toronto, On-tario, M4W 3E2.One No.55 on Reader Service Card

Over 500 software programs formanufacturing are described in the1985 Handbook of ManufacturingSoftware. Programs include inven-tory control, CAD/CAM,robotics, and process control soft-ware. The handbook also covers

the fundamentals of applying com-puters to the manufacturing en-vironment. The handbook isavailable from: SEAL TechnicalPublications, P.O. Box 590,Madison, GA 30650. (404)342-9638.


COP?PUTERnnrirr nnrIN /-1/ ILLINL316 College St.

Toronto, Ontario M5T 1S3

INC.

Toll Free Orders Only1-800.387-1385

Order Checking (416)925-8291Technical Data (416)925-1105

WIRED N TESTED

NEGA-BOARD(A) Tested 64K MEGABOARD with MEGABIOS,Manual and Schematics $549.00(B) Socketed and wave soldered MEGABOARDwith detailed parts list $249.00(C) Memory expansion, each 64K tested $ 75.00(D) Memory chips, 4164-150ns ..9 pcs $ 55.00(E) 256K DRAM, price on request

APPLE® DETACHEDKEYBOARD

1, .,

TheThe illIMIFMARK-II Apserial data (IBM) format. Plugs directly into Apple PCB

$159.00

IBM is a registered trademark ofInternational Business Machines

IBM® STYLE KEYBOARDAt last, a good low cost keyboard for the IBM PC, XT orcompatible machine. Uses capacitive keys, has a verygood "feel", and has TYPEWRITER LAYOUT for easywordprocessing. All this at the very low price of

$139.00

BARE PCB FOR IBM",(A) Colour graphics board $34.95(B) Multifunction board $24.95(C) IBM Disc controller board $19.95(C1) IBM Disc controller with part port $24.95(D) IBM WIN Protype, DB9,25, holes $24.95(E) IBM memory prototype, 256K mem $24.95(F) IBM extender board $19.95(G) Printer Card $14.95(H) 512K memory card $24.95

All cards come with a parts list and placement diagram.We have all the hard to get parts. And PromslEproms

IBM CASE

We have the case for you, the newest type with 8 slotsfor the MBE -XT board, has hinged lid and all mountinghardware $89.95Same as above for MEGABOARD, 7 Slot $99.95Older type, top opening for Apple pcb to look like IBMsystem, holds 2 drives $89.95

Eight CompatibleI/O InterfaceConnectors(Foil PC compallble)1, ompatible with allIBM-PC- plug-in cards)

Special J1Interfacei Allows horizontal moon,ing of compatible expan-sion cards for easy busexpanston and customJontiguring) (Board has62 pin gold plated compat-ible connector)

Extended ROMCapability(Runs an compatible PCROMS) (Jumper program-mable to accommodate allpopular 8K. 1616. 3216 and64K ROM chips and NEWEE ROMS, VPP power pmavailable for EP ROMburning') (ExternalVPP voltage required)

Full Mega -Byte Ram CapacOn board!(Wah parity)

'256K Bytes using 64K chips1 Mega Bytes using 256K chips

Meg..Board® $99.95With full assembly data.Mega-Boerd® , Users manualwith schematic, ap. notes andtheory, etc. $19.95MEGA.BIOS,' , a fully MS-DOS,PC -DOS compatible non -infringing 8103 MSS

EvaluationBoardBoard Kit

DISPLAYTELECOMMUNICATIONSCORPORATION

BOARDStandard Key-board Interlace(Full PC compaltble)

Hardware Reset(Overcomes reset flawSr PC)

Power Connector(Full IBM' pinetticompatible)

8088 ProcessorSame as PC)

8087 NumericProcessor(Same as PC)

PeripheralSupport Circuits(Same' ,,, PC)

ConfigurationSwitches(Same as PC)Speaker/AudioPort(Same as PC)

Wire Wrap AreaTo factlitate special customapphcalanst

FULL IBM - PC'COMPATIBILITY!

rricA.Boar Evaluation Board(Blank board with lull assemblyinstructions and parts list

Includes highest quality PC boardwith gold plating. silk screensolder mask

SHUGART SA455A35-1/4"HALF SIZE DRIVES

40 Track per side Double.sided,double density

Latest head &drive technology

Fast access time

4Two of These Half Size Drives will 21 9.00Fit in the Same Space as 1 Full Size Drive!

SWITCHINGPOWERSUPPLY

110V, 60Hz with Fan and two rearswitched outlets.

100 Watt + 5-10A; + 12-3.5A;5-112A; -12-1/2A $139.00100 Watt + 5-15A; + 12-4.5A; 5-1/2A;12-1/2A $169.00

MBE -XT $49.95

Here It is, a 256K XT compatible 8088 machinethat works like an IBM. Note has 8 slots on 0.8"spacing to use modern XT peripherals, unlikethe BEST which has only 5 on 1" spacing. TheMBE -XT will hold any legal or illegal BIOS orBASIC. We suggest the MEGABIOS, one of thebetter ones available.(A) MBE -XT with assembly data and parts list

$49.95(B) Complete schematics and manual ....$4.95(C) Wave soldered MBE -XT board without anyIC's, all sockets, edge con. R.C. Etchwithmanual and full schematics. You just add IC's

$225.00(D) As above but fully stuffed with all IC's and64K of RAM on board with BIOS and M&S$450.00

MAIL ORDERS: We accept VIA;MC;AMEX;credit cards. Money orders, cheques (2week wait) are also OK. Minimum packingand handling fee $5.00 or 5%, whicheveris larger. The only COD we use is via CAN -PAR (Add $4.00 COD fee) or motor freight.We do not use postal COD at all. All Ont.res. add 7%. All prices are subject tochange without notice. Returns are sub-ject to a 20% restocking charge.

MEGABOARD/MBE-XT PARTS4

A) INTELJAM D IC sets 99.00 N) 62 pin edgeB) 8253.5 S 8.95 coon $2.50C) 8259A $ 8.95 0)5 PIN DIN $1.50D) 8237A-5 $ 19.95 P) Power connector ..$1.50E) 8255A-5 $ 11.95 0)4.7K x 6 sip $0.60F) 8284 $ 9.95 R) 4.7K x 15 ntwk ....$1.00G) 8288 $ 20.00 S) 8.2K x 15 ntwk ....51.50H) 8088 $ 18.00 T)33 Ohm x 8 ntwk ..$1.501)8087 $225.00 U) 4.7K MBE -XTJ) 8272/765 $ 19.95 SIP $0.90K) 100 NS USA delay S 14.95 V) Megaboard prom . . $9.95L) 7 NS US delay ...$ 14.95 W) MEGABOARD BUSM) 50 pf trimcap. .S 1.00 Bar $1.50 ea.

X) .1uf Monolithicceramic caps0.1" or 0.2" $0.15 ea.


By Yin H. Pun

........ .... ....... ..

.... :::. ..

.. .............

1\ '

E , H Fl ETRE1.:1 T E L 0 L.'. T T'H E f F :=; 1- E

Computing TodayProjectile MotionLearn something about the physics of trajectories,or just play a diverting game; a discussion and aApplesoft listing.PROJECTILE motion is often a difficultconcept to grasp at first. Why do objects,ranging from a small baseball to a giganticrocket move in such predictable pathsafter being launched?

Simple projectile motion is easily sim-ulated in real-time on the Apple II's highresolution graphics screen using this pro-gram. If you want to do it analytically, thegame requires a knowledge of parabolicor projectile motion governed by the lawof gravity; if you'd rather just play thegame, it's just as much fun as blastingyour average aliens. The object is to fire aprojectile after calculating its angle andinitial velocity to destroy a target sus-pended in mid-air.

Entering the ProgramFirst boot a DOS 3.3 or a ProDOS 1.0.1disk and get into Applesoft BASIC. Typein the Applesoft program listing. Save itevery now and then (to protect againstcrashes) by typing "SAVE PROJEC-TILE. MOTION". Type "RUN" toexecute it.

Playing the GameThis game is quite educational in teachingthe simple laws of projectile motion. Firstenter the acceleration due to gravity of thesystem. If only the "RETURN" key ispressed the acceleration will default to 10m/s/s, the approximate value on Earth.Use the default value at first. Then experi-30

ment with some absurd values. Here aresome accelerations due to gravity forsome of the planets:

Celestial Body g, m/s/sThe Sun 285The Moon 1.62Mercury 3.76Venus 8.77Earth 9.81Mars 3.80Jupiter 24.9A Black Hole 1000

Fig. 1 A few values for g, the gravitational con-stant.

After you have entered the necessaryinformation, a suspended target resem-bling a balloon is randomly placed on thescreen. It may be as high as 160 metres inthe air or as far away as 280 metres. Youcan enter the angle of your gun from 0 to90 degrees. The height of your gun maybe 0-160 metres high. The speed of yourprojectile can only be positive. With trialand error, you can usually destroy yourtarget in less than ten shots. But, if you arebold enough, you may make precise cal-culations to destroy the target.

A projectile on the moon with low grav-ity requires a low velocity to escape thegravitational pull. A projectile in a blackhole (g 1000 m/s/s) requires more than thespeed of light (300,000 km/s) to escape.However, in accordance with Einstein's

Special Theory of Relativity, the speed oflight can be approached infinitesimallybut never be attained or exceeded by anymaterial object; therefore, this is impossi-ble. Not even light can escape the pull of ablack hole's gravitational field. (That'swhy they're "black").

The Physics InvolvedThe velocity of a projectile is a vectorconsisting of a magnitude (speed) and adirection (the angle). This vector is bro-ken down into two rectangular compo-nents, the horizontal and the vertical. Thehorizontal component of the velocityalways stays constant from the time offiring (neglecting any air friction) sinceno external forces act upon the objecthorizontally. The vertical component,however, is acted upon by the force ofgravity, which is 9.8 m/s/s on Earth. Thisforce produces an acceleration towardsthe surface (Newton's second law). Byconsidering the motion of the projectile astwo independent vectors, its position (ordisplacement from its initial point) can becalculated. The resultant motion takes theshape of a conic section, the parabola.The velocity of the object at any instant isthe general integral.

v =/-a dt isv = -at + K ; K is a constant. It is the

initial vertical velocity of the object.The displacement of the object is the

integral of the velocity:d =/-at + K dt isd = -0.5at2+ Kt + H ; H is a constant.

It is theinitial height from which the object

was launched.Fig. 2 The equations involved in calculating theballistic path if you're keen. Consider "a" tobe negative as upward directions are positive.


By deleting line 570, the projectile willleave its locus of points on the screen as ifthe projectile had been photographed witha strobe light and a camera with its shutteropen.

The MathThe position of the projectile is simplycalculated by two formulas as functions oftime, T.

The horizontal position, X, is calcu-lated by line 540.

X = XV * T

where XV is the horizontal component ofthe initial velocity. T is the time. Sincethere are no external forces acting in thehorizontal direction, the horizontalvelocity remains constant (we neglectwind resistance). Therefore, the displace-ment is directly proportional to the time.

The vertical position, Y, requires morecalculations since it is acted upon by theforce of gravity. However, you mayderive it by simple integral calculus. Dis-placement, velocity and acceleration arefunctions of time so you differentiate andintegrate with respect to time. The changein displacement, called velocity, is thederivative of the displacement calledvelocity. The change in velocity, acceler-

ation, is the derivative of the velocity.Working backwards, in other words, thevelocity is the anti -derivative or integralof the acceleration and displacement is theintegral of the velocity. The accelerationdue to gravity which is constant is "a"downward on Earth.

The vertical position, Y, is calculatedby line 550.

Y = YV * T- (.5 *G *172) + H, whereYV is the vertical component of the initialvelocity. G is the acceleration due to grav-ity and H is the initial height of the gun. AsT increases, the position of the projectilechanges. The equation, of course, is quad-ratic and a parabola would be plotted on arectangular T vs. Y graph. Hence, this pro-jectile motion can also be called parabolicmotion.

LimitationsOf course, this program only provides asimulation of the real world by naturallaws of physics. However, it does proveto be a pretty good approximation.

This program does not consideratmospheric friction of the flying object.Wind and the density of the atmospheredeviate the object from its ideal path. Thecoefficient due to air friction of the pro-

jectile would have to be considered. Thefaster the object goes, the more frictionwould act upon it. Wind would create ahorizontal force, you can replace line 540with:

540 X = XV * T + .5 * HX * T * T

where HX is a constant (the value of thehorizontal acceleration)

to consider a horizontal acceleration.With this horizontal acceleration, theresultant acceleration vector would nolonger be straight down; it would beoblique.

I will leave it to some physicist todestroy the target in one shot by calcula-tion. The hint is to formulate a parabolawhose locus coincides with the location ofthe target.

The applesoft listing appears overleaf

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Auto Answer $159.00

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Computing Today

10 REM 500510

XV = V . COS (TH)YV = V * SIN (TH)

10401050

HCOLOR= 0: NEXTYA = YT

--20--RE PROJECTILE MOTION+

ozO REM MAIN 1,00P W. PROJECTILEMOTION

10601070

PORE--=-1-67Mr0GOTO 910

30 REM * 530 T = 0 1080 YK = 159 - YA* 540 X = XV * T 1090 HPLOT XA,YK TO XA,YK - 7 TO

40 REM * BY YIN H. PUN 550 Y = YV * T - (.5 " G * T 2) XA + 1,YK - 7 TO XA - 1,YK -

50 REM . li

SO = PEEK (SL), iU XA 1,YK - b TO XA - 1

,YK - 6560* 570 HCOLOR= 0 1100 HPLOT XA - 4,YK - 1 TO XA -

60 REM COPYRIGHT (C) 1984*

580590

HPLOT XL,159 - YLIF X 279 THEN GOSUB 1200:

---131 "-HPLOT-`XA

4,YK TO XA + 4,YK TO XA + 4,YK - 1

70 REM BY MOORSHEAD PUBLICATI GOTO 330 - 1,'I ru RA - I,TONS * 600 IF Y 159 THEN 660 K - 3 TO XA + 1,YK - 3 TO XA

80 REM * TORONTO, ONTARIO 610 IF ABS (XA - X) 5 AND ABS + 1,YK* (YA - Y) 7 GOTO 680 1120 HPLOT XA + 1,YK - 3 TO XA +

90 REM 620 IF Y 0 THEN T = 3: GOSUB 8 3,YK - 5 TO XA+ 3,YK - 7: HPLOTA11.1.31____ . GOOUB 1200. GOTO 330 XA - 1,YK - 3 TO XA - 3,YK -630 HCOLOR= 3 5 TO XA - 3,YK - 7

100 : 640 HPLOT X,159 - Y 1130 RETURN110 TEXT : RESTORE : SPEED= 255 650 XL = X:YL = Y 1140 HCOLOR= E:E = ((T 20) AND120 HOME : INVERSE : PRINT "PARA 660 T = T + ST: GOTO 540 3) * 3

BOL.TX.--140T-ION---OF-A-PROJECTILE -640-0EH-TARGET . 1150 FK1N1 1rENORMAL 680 HOME : VTAB 24: PRINT "TARGE 1160 HPLOT XA + 1,YK - 3 TO XA +

130 PRINT T DESTROYED!" 3,YK - 5 TO XA + 3,YK - 7: HPLOT140 PRINT "BY YIN H. PUN" 690 FOR A = 1 TO 100 XA - 1,YK - 3 TO XA - 3,YK -150 PRINT "COPYRIGHT 1984": PRINT 700 SO = PEEK (SL):SO = PEEK (S 5 TO XA - 3,YK - 7

160 PRINT "The object is to destL)POKE 49234,0: POKE 49237,0

11-711--RPLOT XA - 4,1K - i TO-Kik +4,YK - 3710

roy a target by a": PRINT "1 720 SO = PEEK (SL):SO = PEEK (S 1180 RETURNaunched projectile.": PRINT L) 1190 REM THIS ROUTINE SIMULATES

110 PRINT DU730740

POKE 49236,0: POKE 49235,0SO PEEK 1100

A GET STATEMENT"FEES TO_UNPUT-ACCETERATION

E TO": INPUT "GRAVITY IN m/s- .

L)FMiNT ANY KEY CON

TINUE...";2? ";G$ 750 NEXT :T = 0: GOSUB 950 1210 IF PEEK ( - 16384) 14180 G = VAL (G$) 760 POKE 49234,0: POKE 49237,0 1 THEN 1210

190 IF G$ = "" THEN VTAB ( PEEK 770 FOR T = 1 TO 100: NEXTA071A n

1220 POKE - 16368,0C37)1?-ELTABL191.. pwrnty__no!_:_G 780 POPE POE 40235,0 KE1UXN= 10 790 FOR SO = 1 TO 25:T = PEEK (

.

200 POKE 230,64: POKE 28,255: CALL SL): FOR T = 1 TO SO: NEXT Ti 1.

62454 ,SO210 HCOLOR= 3 800 FOR T = 1 TO 3000: NEXT220 B1R RIO rump 110230 REM Randomize position of to

rget820 REM THIS ROUTINE PLOTS EXPLO

SION OF BULLET240 YA = RND ( PEEK (78)): REM S

eed random number generator930 HCOLOR= 3: IF X 269 OR X

10 THEN RETURN840 FOR EN = 1 TO 2

250-4A7= INT ( RNDT1) * 159) 850 YF = 158: HPLOT X,YF TO X + 1260 XA = INT ( RND (1) * 269) + O,YF - 15: HPLOT X,YF TO X -

10 10,YF + 10: HPLOT X,YF TO X -270 GOSUB 1080 5,YF - 7: HPLOT X,YF TO X +280 YT = YA:YS = 159 - YA 5,YF - 719U HPLOT 0,159 TO 279,159 860 SO = PEEK (SL)300 HPLOT 50,159 TO 75,150 TO 97 870 HPLOT X,YF TO X - 7,YF - 4: HPLOT

,120 TO 150,135 TO 200,125 TO X,YF TO X + 7,YF - 4250,159 880 HPLOT X,YF TO X,YF - 10: HPLOT

310 HPLOT 97,120 TO 130,159 X,YF TO X - 10,YF: HPLOT X.Y320 HPLOT 150,135 TO 200,159 F TO X + 10,YF330 REM MAIN ROUTINE 890 SO = PEEK (SL)340 SL = - 16336 900 HCOLOR= 0: NEXT350 EN = 10 910 HCOLOR= T360 ST = .25 920 SO = PEEK (SL)JR) VE = 1UU 930 GOSUB 1080380 HOME 940 RETURN390 VTAB 21 950 : HCOLOR= 2:YA = YS: FOR EN =400 PRINT "Your gun is at the bo 1 TO 2

ttom left." 960 SO = PEEK (SL)41U PRINT "7;F-i-e "Gwffi7s2" V HPLOT XA,YA TO 0,0: HPLOT XA420 PRINT "The target is "XA"m a

way and "YA"m up."430 INPUT "ANGLE IN DEGREES? "pD

,YA TO 0,159: HPLOT XA,YA TO279,159: HPLOT XA,YA TO 279,0

:TH = D * ATN (1) * 4 / 180 980 HPLOT XA,YA TO 150,0: HPLOTXA,YA TO 75,0: HPLOT XA,YA TO

440 IF D 0 OR D 90 THEN PRINT 0,75: HPLOT XA,YA TO 279,80"ANGLE MUST BE BETWEEN 0 AND 990 HPLOT XA,YA TO 0,35: HPLOT X90 DEGREES.": GOTO 430 A,YA TO 0,115: HPLOT XA,YA TO

450 INPUT "HEIGHT IN METRES? "pH 279,119: HPLOT XA,YA TO 279,-4t)

460 IF H 0 OR H 160 THEN PRINT 1000 HPLOT XA,YA TO 0,30: HPLOT"THE HEIGHT MUST BE 160 AN XA,YA TO 0,93: HPLOT XA,YA TOD 0.": GOTO 450 279,85: HPLOT XA,YA TO 279,6

470 INPUT "INITIAL VELOCITY (M/S 0). ;V 1010 : H r 1 r1 . HPLOT

480 IF V 0 THEN PRINT "VELOCI XA,YA TO 150,159: HPLOT XA,YTY MUST BE POSITIVE.": GOTO A TO 225,159470 1020 HPLOT XA,YA TO 40,159: HPLOT

490 REM Remember that the 'x' ye XA,YA TO 110,159: HPLOT XA,Y)

loclty component stays constant.

A Tu 14S,1591030 SO = PEEK (SL)

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Review

OCCASIONALLY I take a 6502 com-puter home so I can do a bit of wordprocessing without the Computing Nowstaff throwing paper airplanes at me. Thecomputer, monitor, fan, and two diskdrives balanced on top of each other makean interesting jiggly tower and an adven-ture of every doorway. And of course, thetrailing power cords wind themselvesaround every table leg like boa con-strictors, pulling disk drives to the floor andscattering bits and bytes everywhere.34

ECS6

An Apple/CPM-compatible in a portablecase complete withdisk drive and monitor;some good ideas andsome bugs.

by Bill Mark wick

To my knowledge, the ECS6 is the firstApple -compatible computer in a truly por-table case; the Apple IIc, while transporta-ble, isn't quite the same idea because it hasa separate monitor and power supply.

Opening It UpThe computer in its shut state looks some-what like a portable sewing machine andis about the same size. Unscrewing twoknobs lets the bottom come off and revealits new personality as a keyboard. It's

vaguely like an IBM type, but with a fewof key legends altered. The function keyshave specific uses rather than being pro-grammable, the Alt key now says PWR(although it doesn't actually do anything),the Print Screen is now another Controlkey, and so on.

On the front panel you'll find a nine -inch amber monitor, one half -height diskdrive mounted vertically, jacks for videoand cassettes, and knockout slots whichwill accept three 25 -pin D connectors and


one 50 -pin. There's a switch marked40/80 and the usual monitor adjustmentcontrols for horizontal and vertical.

On top is a round plastic cover whichunlatches to reveal the power cord. If youpull out the power cord holder, you'll beholding the mounting panel for thefan while peering into the innards of thecomputer. Inside you'll see aconventional -looking motherboard witheight slots for peripheral cards. In Slot 0 isthe small card which holds the ROMs, andin Slot 6 lives the disk controller; the80 -column card for Slot 3 is optional, andrequires figuring out the unmarked videocables. Eventually, you'll stumble ontowhich one goes to the 80 -column card andwhich one to the 40 -column output. Atthe rear is a standard switching power sup-ply and beside it the switching regulatorfor the monitor. There's 64K of RAM in4164 -type ICs tucked under the monitortube.

Although you can get cards in and outnicely through the fan opening, the work-ings are easier to examine with the casetop off; this requires removing six screws.A few drawbacks reveal themselves. Oneis that the front panel cassette jacks havecables which are supposed to plug into themotherboard and can't; the disk drivemounting panel is in the way. Another isthat the disk ribbon cable is folded andsecured with a metal loop; this loop tin-kled unnervingly against the controllercard. The power cord for the fan wiggledloosely in space as well.

None of these wandering wires causedany immediate problems, but the mainand monitor power switches come loose ifyou take the top off because they're afriction fit between the case halves.Again, this didn't cause anything butannoyance, but I'm thinking of the trust-ing soul who gives his ECS6 to the airlinefreight handlers. No doubt he jets off,blissfully unaware that his powerswitches have either been poked into thecase or torn out by the roots.

Lastly, the threaded knobs which hold.the keyboard can be inserted into holes inthe bottom of the main case to tilt it up forviewing. They don't thread in, however,but sit rather insecurely.

Testing It OutRemove the coil -cord from its groove inthe keyboard and plug in the DIN con-nector to the front panel. Switch on, andyou'll see a sharp, easy -to -read image onthe amber screen. Insert a DOS disk andpress Boot; PR -6 will automaticallyappear on the screen and DOS loads itselfin.

Working with BASIC was convenient;most of the often -used commands appearat a single keystroke. The CLR/EOL keyremains a mystery; though it returnedElectronics Today January 1985

The interior of the ECS6. The cords at the front edge are for the optional 80 -column card; theone at the rear is for the fan.

ASCII 27 (Escape), it didn't seem toaffect anything. There are two Controlkeys on opposite sides since the IBM -style has more keys than an Apple -com-patible needs, and I found this very nicefor WordStar and its many control func-tions. The Tab key doesn't actually tab,

but prints the word on the screen for usewith HTAB and VTAB.

Function KeysOn the left side of the keyboard areBASIC commands such as Run, List,Save, Load, etc. In addition, lots of things

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ECS6 Review

are stored away in ROM and can be acti-vated via Control/Shift and one other key.The numerals, for instance, will load inlittle graphics demonstration programsand run them; Control -Shift -7 loads in asimple arithmetic game. The most usefulfeature would be the string buffersassigned to 12 of the letter keys. To usethis, you would type Control -Shift -A, forinstance, and then a string of up to 40characters. This string will now appearwhenever you type Control -Shift -Aagain; very useful for inserting phrasesand BASIC statements that you use a lot.As an example, if you need a delay loop toallow time for reading text in a program,you could insert a FOR -NEXT loop inbuffer A and recall it as needed.

The next letter up in the alphabet clearsthe buffer below it; for instance, Control -Shift -B clears buffer A. If you can't keepthem all straight, Control -Shift -Z dis-plays all the buffers and their contents.

CP/MIf you insert a CP/M disk and press Boot,you're away. Beside the 6502 on themotherboard lives a Z80; add the optional80 -column card and the world of CP/Msoftware is yours. Word processors aresurprisingly comfortable to use on thesmall screen; the text is about the width ofa paperback book. It was a treat to havethe 40/80 -column switch on the frontpanel; dual- processor fans will welcomethe relief from having to reach around thecomputer and fumble the video cord intoanother jack.

As I was doodling away, I heard a clunkfrom within. I opened the fan door andfound that the tiny speaker had comeloose from its double -sided tape and wasadrift amongst the RAM. Gasp! Nothingshorted out, but I'd certainly prefer a bettermounting method, especially for a portablecomputer.

If you'd like a bigger screen, you canpower down the monitor separately andconnect a bigger one to the front panel jack.If you do a lot of telecommunications andhave a serial card, you can easily fit anRS232 jack to the front panel; there aremounting posts on the inside. You can alsofit a DIN -type jack if you prefer. Space andjacks are provided for an optional RF mod-ulator should you decide (for some reason)to run the computer into a TV. The modu-lator fastens to the inside of the front panelwith double -sided tape.

More OperatingThere's another leftover key on the IBM -style keyboard: FUNC. This didn't func.It didn't seem to have any use at all,though it returned an ASCII value of 31.There's also a HOME key, which is nicefor clearing the screen quickly.

I set the keyboard down on top of thecomputer and went over to another desk.

Suddenly there sounded a loud peepingfrom the ECS6; when I returned to see ifghosts were typing at it, the screen hadfilled up with gibberish. Turned out thatboth the monitor and the keyboard areunshielded, and the flyback pulses fromthe tube just drove the system crazy. Itdidn't cause any harm, but you have to becareful where you set the keyboard.

The fan was nice and quiet, but I foundthat the disk drive ribbon cable (that peskything again) could lazily coil upwards andstop the prop from turning. This could havebeen easily cured with cable ties.SummaryWould I buy an ECS6? Yes, but with afew minor reservations. The BASIC anddisk drive appear to be fully Apple -com-patible, the keyboard has some nice func-tion keys, it's a great looking box with afirst-rate monitor, and best of all, it'struly portable. On the other side of thecoin, it's obviously been rushed into pro-duction without much care being takenwith little things. The factory should:

1. Tie back the ribbon cables with plasticties.2. Protect the exposed power switches.3. Label all internal cables.4. Shield the keyboard or the monitor.5. Fasten the speaker mechanically.

These are minor problems, but annoy-ing nonetheless. Since our test version wasone of the early models, it's entirely possi-ble that by now everything has been cor-rected on retail models. The cost of theunit at $1295 is a tad higher than buyingthe equivalent computing power inseparate boxes; it generally costs more tohave things in nice packages.

Quick ReferenceECS6 Apple -compatible portable

CPU: dual, 6502, Z80ARAM: 64KMonitor: 9 inch amberDisk Drive: 5-1/4 half -height, includes

controllerOptions: 80 -columns, second drive,

etc.Weight: 11.3 kg.Other: 80 column switch on front

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HammondRadio

Museum

The radio equipment of yesteryear is preserved inHammond's Guelph museum; here are some

nostalgic memories.

QUICK now! What's the single most im-portant development which enabled us toget to the Moon? Electronics: it also laun-ched many careers, specifically Radio,long before that momentous event. AndFred Hammond of Guelph, Ontario hasrecorded "radio's long walk" in arecently -enlarged Radio Museum on thetop floor of the parent company's sprawl-ing electronics Plant on the north-westedge of Guelph, Ontario. Located onHighway #7 about 48 km north of thetelephone city, Brantford, the Museum isin good company, for telephone and radio38

By James W. Essex

because synonymous with the spokenword since the early 1900's.

Most of us knew Fred through Ham-mond transformers, found everywheresince the early days of radio. Fred Ham-mond, with three brothers, helped it allhappen then, and though now semi-retired and the surviving brother of thetriumvirate, Fred's determined that weremember the first halting steps of radiowith a "Radio Museum".

I first met Fred after I'd assumedcharge of a radio station near Guelph.CJCS Stratford was my first job on "civ-vy street" after stowing the Navy uniformof 1945 and giving a fond farewell to theKing's coin. My frustrations were similarto Fred's, however, for he had to combstore -rooms and attics where vintageradios were left long forgotten while I fac-ed the prospect of a transmission -lessChristmas because an equally antiquatedtransmitter which failed on the mostlucrative business day of the year,Christmas 1945.


"I'll see what I can do to get youback on the air," replied Fred in responseto my cry for help. Remember, this wasthe day of entrepreneurs like Roy Thom-son where baling wire and a few tubesconstituted a transmitter, and anyonewith more nerve than common sensecould set up shop. In fact, Thomson,along with Jack Kent Cooke (who went onto become a top sports promoter in LosAngeles), got Stratford its first commer-cial radio license in 1937 after another setof brothers named Higgins built 10 A KStratford about 1933. This was my in-heritance; much like Fred Hammond'sradio memorabilia is today. And Thom-son has his "Roy Thomson Hall" indowntown Toronto.

The museum contains everything youalways wanted to know about radio butwere afraid to ask. How many, for exam-ple, recall the famous "Scott" radio con-taining a nickel -plated chassis? Even tubeshields were plated, the Cadillacs of thetrade. Or the opposite extreme, the hum-ble crystal -set which provided the gluewhich held the fledgling industry togetherin the early years, but which tried the pa-tience of the most tender souls trying tofind the "hot -spot" so he could listen toAmos 'n Andy.

Hammond has a radio from everydecade, including the type which receivedthe first Presidential returns from pioneerRadio Station KDKA Pittsburg. When"Harding Wins" burst forth over the airwaves the night of November 2nd, 1920, itmarked a new era in radio beating thenewspapers to the punch, and instantcommunications was begun.

Perhaps about a hundred homespossessed receiving sets then. By 1929,U.S. radio sales totalled nearly $950million as Americans paid upwards of$118. (fantastic then) for elaborate con-sole models with up to 14 tubes and aloud -speaker, of which Fred has two, stillin their shiny, hardwood hand -rubbedwalnut cabinets. Motorola invented thecar radio that year and Fred has some ofthese, too. The loudspeaker was mountedunder the all wood floor -boards then invogue while the radio itself was twice thesize of a sportsman's tackle box. Despitesize, this new concept became firmlyestablished as the forerunner of the sleek,miniaturized radio and tape players com-monplace today in autos. Even the stockcrash of that year couldn't stifle radio.People may have been short of money in"the Hungry Thirties" after the MarketCrash of 1929, but they always seemed tofind money for entertainment, as the widerange of taste reflected in Fred Ham-mond's equally huge display of the bestfrom that era testifies.

In the Museum today you'll findradios heard only by earphones to hugeones driving loud -speakers following theElectronics Today January 1985

advent of the push-pull triode circuits us-ing the type 45 triode tube which radiatedenough heat to warm the living -roomwall. (It's interesting to note that today'skids have brought us full circle as theywalk the streets, headphones clampedtightly to their ears. Early pioneers did thesame thing then, only in the living -roomsof the nation.) Loudspeakers whichfollowed brought families together again.Fred has many early examples of thisdevelopment, from the early classic hornssymbolized by the puppy -dog and RCA's"His Master's Voice" to the hugedynamic speakers which eventually wentinto Movie Houses, and which made AlJolson's "Sonny Boy" synonymous withmagic.

To see Hammond's Museum is to enjoya commentary on the social mores ofyesteryear. That noble experiment of the

Some of Fred Hammond's DX cards confirm-ing long-distance reception. Below is aStromberg-Carlson receiver of the 1920's; thethree RF stages had to be tuned exactly witheach other. All photos by Dave and J. W.Essex.

1920's, Prohibition, is here also whenradio complemented President Hoover'sidea. Prohibition was not much of a suc-cess and, after 13 years, it was abandonedin favour of a new morality. Prohibitionwas at last cancelled with the Twenty -FirstAmendment, ironically announced viaRadio, of course to an expectant publicwhich had had enough.

One buff even had his picture taken sit-ting with a pair of headphones clappedtightly upon his ears with a bottle of "il-legal" whiskey at his side, ready to con-sume as soon as the repeal was flashedacross the nation. Colourful reports con-tinued over Radio, attracting still morelisteners captured by the sheer excitement

engendered by news "greats" like LowellThomas, as Al Capone and rival gangs inChicago vied for power. The timesushered in a new era of comedy with JackBenny and Fred Allen and a public growntired of violence. A peculiar appendage ofthat age was the proliferation of violinscarried in the streets of Chicago which ledmany to remark "it was a musical city".Many types of radios, like the radioswhich carried the action then, are in theMuseum today, while popular songs suchas "I'll see you in My Dreams" lent an airof unreality to the wonder of the agewhich could bring the world into your liv-ing room without wires.

Fred points with pride to an earlywireless, built by a Canadian, Colin B.Kennedy of Teeswater, Ontario, whopreceded Hammond's own flirtation withmaking radio receivers and who also fail-ed to survive in a rapidly competitivemarket. Hammond continued in compo-nent manufacture and today is one of thelarger producers of power transformersfor electronics, while the Kennedy is heardno more except in the Museum; it sharesthe fate of the crack InternationalLimited, the huge steam -drawn trainwhich raced between Montreal andToronto, equipped with radio (ElectronicsToday, December, 1981). Now bothsteam and that form of radio are gone butartifacts of that era can be seen today inthe Museum. (An actual steam engine tooof that era rests by the CNR tracks atGuelph's VIA Rail Station - a brief ridefrom the Museum). Not forgotten is thetremendous advance in the vacuum tubewhich Fred has lovingly displayed to ad-vantage in huge racks. There are theUV200's, the 227's and the 2A5's, the6L6's which opened our eyes by showingwhat a pentode power stage in a radiocould achieve in loudness, up to the largertransmitter tubes like the 810's, 812's andthe air-cooled 6066's by Western Electric,only one of the many type of transmittertubes which helped make it all possible.Decorating the door frame is a hugewater-cooled transmitter tube whichstands as high as the door, a symbol of theepitome of power of Radio's heyday.

The Museum hasn't forgotten theearly "radio pioneers extraordinaire": theRadio Amateur. Fred has his own high-powered short-wave transmitter which hestill uses to contact world listeners,evidenced by DX cards from all over theglobe. Amateur radio receivers includingthe famous Hallicrafters are here, as wellas an AR -88 built by RCA which were us-ed widely in World War Two by the AirForce, Navy, and some Army units. TheMuseum has early turntables used whenradio consisted mainly of a phonographand a microphone, epitomized by menlike "Doc" Cruikshanks of CKNXWingham. Something resembling protec-

39

Hammond Radiotionism today was evidenced in early radiotoo; if you wanted a Western Electricmicrophone, for example, you had to buya whole transmitter (theirs, of course).

Diversity receivers are also displayed.They were the set-ups whereby severalreceivers at varying locations were phasedto a common listening post in order toreduce "fading", the characteristic "wavesound" of overseas broadcasters. Theseof course have been phased out too, madeobsolete by the satellite where steady -signal strength from overseas is not just ahope but a fact. Communications from A sampling of various loudspeakers along with various types of radio sets.

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the Moon itself proved you didn't needgobs of power to get distance, nor for thatmatter knowledge of the vagaries of theKennelly -Heaviside Layer, which is whatthe "Diversity Receiver" tried to compen-sate for.

Today, Fred and I laugh about howwe got that recalcitrant long -ago transmit-ter in Stratford back "on the air": he, bysending me a box full of miscellaneousspare parts on the next train; me, by pick-ing over them judiciously until I foundjust the right combination of capacitors toreplace the shorted Final which poppedbecause of an ice storm shorting theantenna lead-in on the hotel roof whereour 50 watt transmitter was located.

To see the Museum, go to the recep-tion area in the office on Curtis St.,Guelph during business hours and request"to see the Museum". Memorabilia ofmen not only like Lee De Forest, butEdison, Marconi, Fessenden and othersare here.

And as Fred locked the Museum doorbehind us, the darkness which haddescended emphasized a brilliant moonwhich hung in the sky outside. "Isn't itbeautiful," said Fred, looking up but nottaking into account a new generation hadalready began a museum of their own upthere. For on that heavenly body lay theremnants of man's "greatest step" and aplaque marking the event; perhaps oneday younger minds will tour much as I haddone embracing the yesteryear of Radio inHammond's Museum, today. Such hasbeen the "leap" of Radio.

40 Circle No. 32 on Reader Service Card Electronics Today January 1985

SoftwareNow!

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Be a point of sale terminal, adjusting the stock data base on line. Produce individual packing lists. Generate a customer list to be used in mass mailings. Run on any CP/M or MS -DOE based computer, even an Apple II running with a softcard.

Stockboy is written in Microsoft BASIC, and is designed to be easily altered to suit your needs. It can becompiled using BASCOM if you desire. It is designed for use by non -technical operators.

Available for: CP/M and PC formats

$29.95 most systems $34.95 for 8"Ontario residents add 7% PST.

AppleWordstar Fixer

Apples and Wordstar are not entirely friendly. Applecompatible systems equipped with Videx type eighty -column cards do a number of unpleasant things tothis popular word processor. While there are simplecures for this... they all involve some delicate codehacking.

The Fixer solves this problem. Place it on thesame disk as your copy of WS.COM, type FIXER andafter a suitable amount of disk noise version 3.0, youwill have APWS.COM on there too. This version ofWordstar includes special patching and unhookingcode which runs each time you boot Wordstar, andmakes your fruit behave as it should. It releases thecontrol K's, translates the left arrow key to a deletecharacter, and patches Unitron keyboards.

In additional all of this, the fixer allows you toset some of the defaults ,of Wordstar which theMicroPro INSTALL Package doesn't really get to. Allof these features are menu driven in English for ab-solute non -technical operation.

Fixed Wordstar will run in either 44K or 56K CP/M.

Available for.Apple II + CP/M only. $19.95Ontario Residents add 7% P.S.T.

MDM730MDM730 is one of the most powerful MODEM7 pro-grams available ... and the Computing Now! version ofMDM730 incorporates features not available in thepublic domain editions. If you are into telecommunica-tions, bulletin boards and downloading software yourlife will be full and meaningful with this code. Forbackground on MDM730, see July 1984 ComputingNow!. Consider the facilities.

Terminal program which works at any baud rate. Ten programmable macro function keys. Thirty six number phone library. Christensen software transfer protocol. User settable toggles for line feeds, ON-XOFF and

so on. Extensive help menus. Baud rate selection on the fly (or the spider). ASCII dump and capture. Status menu Many more features.

In addition to all this splendor, however, we've addeddialing support for the Apple version. While the standardMDM730 cannot dial unless it's hooked to a HayesSmartmodem, we've added patches to it to allow it to dopin twenty five pulse dialling and to dial through theHayes Micromodem II and the SSM card. The Com-puting Now! MDM730 will also

Select a number from the library and dial it Accept a hand entered number and dial it Wait for carrier Log you onto the remote system if it's free Optionally autodial if the remote board is busy. Count the number of attempts at dialling the

remote BBS.

The Computing Now! MDM730 package is available for

The Hayes Micromodem II. The SSM 300 Baud modem card. The PDA 232C serial card with external modem.

The PDA 232C package includes versions supportingboth the Smartmodem and a dumb modem with pintwenty five line control. such as the Novation AutoCat.Also included with each package are utilities to permiteasy alteration of the phone number library and thefunction key macro strings plus an extensive documen-tation file.The source code file for this program is over a hundredand fifty kilobytes long. It cannot be hacked on a stan-dard Apple. We patched it on a larger machine anddownloaded it. As such, we're pretty sure that MDM730with these features is unavailable elsewhere.

Available for: Apple II +CP/M 2.2. systems

TRS-80 Model II (complete withthe above applicable features)

Please specify modem versionfrom above list. $29.95Ontario residents add 7% PST.Fine Print:The original MDM730 code is in the public domain. Weare offering this part of the program without cost. Thecharges for this package are for the patches created byComputing Now! and to defer the cost of handling andpostage.

This software is guaranteed to work correctly if properlyapplied. The serial cards on Apple and compatiblesystems must be installed in slot two with at least 48Kof RAM running Microsoft CP/M 2.2. The PDA 232C ver-sion will require the availability of either a Hayes Smart -Modem or a modem with pin twenty five line control todial. Users of the SSM card version may experiencesome difficulty in detecting extremely faint carriers onolder versions of this card.

FormatsWhere CP/M is shown, the following formats areavailable:

Apple II + CPIM (see below)Access Matrix, Morrow Micro Decision, Superbrain,Xerox/Cromenco', Epson OX-10VD, Sanyo MBC1000,Nelma Persona, Kaypro II, Osborne Single Density',Osborne Double Density, Systel/Olympia, 3R Avatar,Attache, Televideo, Lobo Max -80', DEC VT -180, CasioFP -1000, Micromate, Zorba, 8 inch SSSD'

'Software marked with an asterisk is the higher pricequoted.

MDM730 for the Apple II + CP/M requires two disks andis at the higher price.

PCAvailable for the IBM PC and genuine compatibles.AppleDOSFor Apple II + and genuine compatible systems.TRS-80 Model II CP/MWill operate under either Lifeboat or Pickles and TroutCP/M.

Steve's CP/M Wunderdisk!Volume the First

In the course of doing the last year or so of ComputingNow! we've generated a lot of code. We've collectedall the programs we've written... some of which havenever been published in any of our magazines... andput 'em all on one disk. Included are things like STAR,the Gemini 10 printer setup, the Last WordstarUnhook, CPMAP and the CPIM HOST program, com-plete with several unreleased support programs.

The Wunderdisk is the best collection of trickyCPIM routines on the planet. ideal for anyone whowants to get inside this powerful operating systemand sing. It's also the best documented... the pro.grams, for the most part, are written up in issues ofComputing Now!The Wunderdisk is available for: CPIM $19.95

Ontario Residents add 7% PST.

Gemini WordStarPRESS

The WordStar printing function is agonizingly slow.It's also not very obliging in regards to where it putsits page numbers and things like headers.

PRESS is a utility which handles the formattedprinting of all sorts of text files, be they manuscripts.drafts, program listings... anything that you'd nor-mally want printed out in page form. It installs theheader of your choice at the top of each page andslaps the page number beside it.

It also gives you a running count of the number ofcharacters, lines and pages having hit the printer asyou go. It allows you to have your documents printedout in a variety of type size and style permutations.commensurate with the capabilities of your printer.

Most important, however, PRESS will send text toyour printer, formatted and all, as fast as your printercan accept it. It will even adjust the high bits of Word-Star files to avoid selecting the Sanskrit characterset.

PRESS comes configured for the Gemini 10X and15X printers. It will, in fact, be quite happy with mostEpson compatible dot matrix printers. A version isalso supplied for use with letter quality daisy wheelprinters.

PRESS is a simple to use package which com-municates with you in plain -English.

Available for: CP/M $19.95Ontario Residents add 7% PST.

Software Services,Moorshead Publications25 Overlea Boulevard, Suite 601Toronto, Ont. M4H 1 B1

MoorsheadPublications Almost Free Software

Almost Free I Almost FreeSoftware #1 Software #2

Almost FreeSoftware #3

Almost Free Software #1, /2 and #3 are for CP/M and are available in a variety of formats: Apple // + CPIM, 8 InchSSSD, Access Matrix, Morrow Micro Decision, Superbrain, Xerox/Cromemco, Epson OX-10VD, Sanyo MBC 1000,Nelma Persona, Kaypro II, Osborne Single' and double densities, Televideo, DEC VT -180, Casio FP -1000, Zorba.

-single density formats require two disks. The package cost for these formats is $19.95

Modem7. Allows you to communicatewith any CPIM based system anddownload files. Complete details were inComputing Now! November 1983.

PACMAN. You can actually play PAC -MAN without graphics, and it works pret-ty fast.

FORTH. A complete up-to-date version ofFIG FORTH, complete with its own inter-nal DOS.

DUU. The ultimate disk utility allowingyou to recover accidentally erased diskfiles, fix gorched files, rebuild and modifyyour system. A real gem.

D. A sorted directory program that tellsyou how big your files are and how muchspace is left on the disk.

USO/SO. Lets you compress and uncom-press files. You can pack about 40%more stuff on a disk with this system.

Finance. A fairly sophisticated financialpackage written in easily understand-able, modifiable Microsoft BASIC.

BADLIM. Ever had to throw out a diskwith a single bad sector? This isolatesbad sectors into an invisible file, makingthe rest of the disk useable.

DISK. Allows you to move whole massesof files from disk to disk without having todo every one by hand, you can also viewand erase files with little typing.

QUEST. A "Dungeons and Dragons" typegame.

STOCKS. This is a complete stockmanagement program in BASIC.

SEE. Also known as TYPE17, will TYPEany file, squeezed or not allowing you tokeep documents in compressed formwhile still being able to read them.

Order as AFS #1and specify system

BISHOW. Th ultimate file typer, BISHOWversion 3.1 will type squeezed or un-squeezed files and allow you to type fileswhich are in libraries (see LU, below).However, it also pages in both directions,so if you miss something, you can backup and see it again.

LU. Every CPIM file takes up unnecessaryoverhead. If you want to store lots of datain a small space, you'll want LU, thelibrary utility. It permits any number of in-dividual files to be stored in one big fileand cracked apart again.

RACQUEL. Everyone should have oneprinter picture in their disk collection.

MORTGAGE. This is a very fancy mort-gage amortization program which willproduce a variety of amortization tables.

NSBASIC. Large disk BASIC packages,such as MBASIC, are great... and very ex-pensive. This one, however, is free... andevery bit as powerful as many commer-cial programs. It's compatible with NorthStar BASIC, so you'll have no problem fin-ding a manual for it.

280ASM. This is a complete assemblerpackage which uses true Zilog Z80mnemonics. It has a rich vocabulary ofpseudo-ops and will allow you to use thefull power of your Z80 based machine...much of which can't be handled by ASMor MAC.

VFILE Easily the ultimate disk utility,VFILE shows you a full screen presenta-tion of what's on your disk and allows youto mass move and delete files using atwo-dimensional cursor. It has heaps offeatures, a built-in help file and works ex-tremely fast.

ROMAN. This is a silly little programwhich figures out Roman numerals foryou. However, silly programs are so muchfun...

CATCHUM. If you like the fast pace andincredible realism of Pacman, you'll goquietly insane over Catchum... whichplays basically the same game usingASCII characters. Watch little "C's" gob-ble periods while you try to avoid thedeadly "A's"... It's a scream.


All of this software has been obtained from public ac-cess sources and is believed to be in the public domain.The prices of the disks defer the cost of reproducingthem and mailing them, plus the cost of the medium.The software itself is offered without charge. A fewitems include messages imbedded in the code askingfor voluntary donations on behalf of the authors.

Moorshead Publications warrants that the softwareis readable and if there are defects in the medium, wewill replace it free of charge. While considerable efforthas been made to ensure that programs are thoroughlydebugged, we are unable to assist in adapting them foryour own applications.

OIL. This is an interesting simulation ofthe workings of the oil industry. It can beapproached as either a game or a fairlysophisticated model.

CHESS. This program really does play amean game of chess. It has an on -screendisplay of the board, a choice of coloursand selectable levels of look ahead.

DEBUG. The DDT debugger is good butthis offers heaps of facilities that DDTcan't and does symbolic debugging... it'salmost like being able to step, trace anddisassemble through your source listing.

DU87. The older DUU program does havesome limitations. This version overcomesthem all and adds some valuablecapacities. It will adapt itself to anysystem. You can search, map and dumpdisk sectors or files. It's invaluable inrecovering damaged files, too.

ELIZA. This classic program is a microcomputer head shrinker... It runs underMBASIC, and, with very little imagination,you will be able to believe that you areconversing with a real psychiatrist.

LADDER. This is... this program is weird.It's Donkey Kong in ASCII. It's fast,bizarre and good for hours of eye strain.

QUIKKEY. Programmable function keysallow you to hit one key to issue a multi -character command. This tiny utilityallows you to define as many functionsas you want using infrequently used con-trol codes and to change them at anytime... even from within another program.

RESOURCE. While a debugger will allowyou to disassemble small bits of codeeasily enough, only a true text baseddisassembler can take a COM file andmake source out of it again. This is one ofthe best ones available.


$16.95 eachExcept for 8" disks and those withtwo disks which are marked with anasterisk (*) above which are:

$19.95Ontario Residents add 7% P.S.T.

Almost FreePC Software #1

For IBM PC's and genuine com-patibles. Available in Double -Sided or two Single -SidedDisks.'

PCWRITE. While not quite Wordstar fonothing, this package comes extremelyclose to equalling the power of commer-cial word processors costing five or sixbills. It has full screen editing, cursormovement with the cursor mover keypad,help screens and all the features of theexpensive trolls.

SOLFE. This is a small BASIC programthat plays baroque music. It's also afabulous tutorial on how to use BASICA'ssound statements.

PC -TALK. A Telecommunicatonspackage for the IBM PC which does filetransfers in both ASCII dump andMODEM7/X-MODEM protocols andcomes with... get this... 119424 bytes ofdocumentation.

SD. This sorted directory program pro-duces displays which are a lot morereadable than those spewed out by typingDIR.

FORTH. This is a small FORTH inMicrosoft BASIC. You can build on theprimitives intregral with the language.

LIFE. An implementation of the classicecology game written in 8088 assembler.

MAGDALEN This is another BASIC musicprogram.

CASHACC. This is a fairly sophisticatedcash acquisition and limited accountingpackage written in BASIC. It isn't exactlyBPI, but it's a lot less expensive.

DATAFILE. This is a simple data basemanager written in... yes, trusty MicrosoftBASIC.

UNWS. Wordstar has this unusual pro-pensity for setting the high order bits onsome of the characters in the files itcreates. Here's a utility to strip the bitsand "unWordstar" the test. Theassembler source for this one is provided.

HOST2. This is a package including theBASIC source and a DOC file to allowusers with Smart -Modems to access theirPC's remotely. It's a hacker's delight.

Order as AFPCS #1Specify Double -Sided or

2x Single -Sided.*

Software ServicesMoorshead Publications

25 Overlea Boulevard,Suite 601,

Toronto, Ontario M4H 1B1

We justcouldn't resist.

We said we'd never do another dealer ad.But we just had to show you our new packaging.You see, we're spending millions on advertising to

show it to your customers.Which means they could come through your door

looking for it. Any minute now.And if that doesn't have you running to the phone

to stock up, consider all this.The new life -time warranty on Dysan®'s 100%

surface certified diskettes is another clear statement of ourbetter quality.

New Point -of -Purchase displays, dealer incentives,plus product training, free sales manuals and a toll -freehotline.

Now that you've seen our new box and what's in it

Warranty details inside package. Dysan is a registered trademark of Dysan Corporation.© 1984, Dysan Corporation.Dealer Inquiries Invited

for you, we'll try not to do this again.But if something comes up, well, we know you'll

understand.To order more diskettes contact your Dysan

distributor and/or if you wish to find out how you can bea Dysan dealer call 1-800-387-9635.

DYSAN CANADA INC., 80 Riviera Drive,Markham, Ontario L3R 2L6.

Dysan®Somebody has to be better

than everybody else.

Circuit IdeasAnalog TemperatureSensorTHE temperature sensor is an LM334 cur-rent regulator (ICI), and RI is the loadresistor. The output current of IC1 is con-trolled by a discrete resistor, which is R2in this circuit. Output currents of between1 microamp and 10 milliamps can be ac-commodated, and the output current isapproximately equal to 0.0677 divided bythe value of R2 in ohms. Using thespecified value for R2 this gives a nominaloutput current of 100 microamps. This islow enough to ensure minimal dissipationand self heating of the sensor, but is largeenough to avoid problems with noise pick-up in the lead to the sensor.

IC2a is used to amplify the output ofthe sensor, and it is a straightforward non -inverting mode operational amplifier cir-cuit. It is not advisable to use a substitutefor IC2 as most operational amplifiershave an output stage which cannot swingto a sufficiently low voltage to give correctoperation in this circuit. ICla provides alow output impedance, and this is impor-.tant since there is not a great excess ofoutput voltage swing available from theamplifier, and a medium or high outputimpedance would effectively reduce thisvoltage swing by a substantial amount dueto the loading by the meter circuit.

On the other side of the bridge circuitIC3 provides a well stabilised 5 volt supp-ly, RV2 taps off a suitable proportion ofthis to balance the circuit with the sensorat zero degrees; and IC2b acts as the buf-

OUT

NOTES:IC1 = LM3341C2 = LM358IC3 = 78L06

C 1 .mim.100n.'

IC1LM334

R

3

R110k

R2680R

R310k

2

8

IC2aLM358

R410k

R5200k

NORM

CHECK

SW1a

ME150uA

1

1kR6

SW1b

RV14k7

IC2bLM358

R733k

6

R822k

IC378L05

COM

RV222k

IN

100n

/PISW2ON/OFF

B19V

PP3

fer amplifier. Again, a low output im-pedance here is important, in order toavoid significant desensitising of the metercircuit. IC1 is powered from the stabilised5 volt supply as this gives slightly improv-ed long term stability and accuracy.

With SW1 in the "normal" positionthe meter is fed from the bridge circuit viaR6 and RV1. The later is adjusted to givethe unit the correct level of full scale sen-sitivity. With SW1 set to the "check"

position the meter is connected across thebattery via series resistor R5. This resistorgives the meter a full scale sensitivity of 10volts so that it can be used to check thesupply voltage. Accurate results are ob-tained with supply voltages of down toabout 8 volts or a little less, but the bat-tery should be replaced when its potentialfalls significantly below 8 volts. The cur-rent consumption of the circuit is onlyabout 4 to 4.5 milliamps, incidently.

Hiss ReducerBy S.P. Giles

THE circuit goes some ways towards of-fering a cheap reduction in the annoyinghiss present on bad VHF reception signalsand hissy tape recordings. It is based onthe principle that two signals equal in allrespects other than phase will cancel outwhen mixed together. If we create an out -of -phase version of the hiss and mix itwith the original, it will cancel out.

The signal to be cleaned up is DCblocked by Cl and then fed into twoseparate paths, to mixer ICIb's invertinginput via R5 and into IC I a. The latter is aunity gain inverting amp which inverts thehigh frequency content of the input signalpassed through by C2, C3 or C4. The IC1a output is then passed to mixer IC1b viaR4 and PRI, which for best results shouldbe a multiturn preset.

To set up, connect a temporary linkbetween RI and ICIa's inverting input,which will allow ICla to pass all of the in -


put. Hook up the input to a radio tuned toa hissy VHF station and the output to anamplifier. Adjust PRI for minimum out-put - headphones would help here. Nowremove the temporary link and make sureSI is switch to position (a); you shouldhear the original signal with its hiss. Mov-ing SI to position (b), (c) and (d) willresult in the hiss gradually becoming less

audible with position (d) giving the mostdramatic reduction at the expense of los-ing a little high frequency response.

The values of C2, C3 and C4 can bealtered to suit the individual ICI, a dualop -amp, should of course be a low noisetype such as NE5532 or TL072 and C2-4should of course be polyester types.

41

Circuit Ideas

A440 Tuning ReferenceBy C. RobertsonTHIS circuit was developed as a result of ademand by several friends for a cheap andreliable A440 tuning reference whichcould be connected to an exisitingamplifier/studio talkback system. Thefrequency reference used was a 4.433MHz crystal, this having the advantage ofbeing cheap, accurate and readilyavailable.

If 4.433 Hz is divided by 10075 or10011101011011, the resultant frequencyis exactly 440 Hz. However, in order tosimplify the circuit, this is rounded to10076 or 100111010111002. This gives aresolution of 0.5% which is quite suffi-cient for all but the most critical of ap-

plications, bearing in mind that a pitchdifference of about 6% is equivalent toone semitone.

The crystal oscillator based round T1has its output divided by two by ICla, aD -type flip-flop which subsequently feedsthe clock input of the 12 stage ripplecounter, IC2. The appropriate outputs ofthe counter are ANDed via IC3 and Q2and fed back to the reset inputs of bothIC2 and ICla, (Q2 is an NPN type inorder to reduce power consumption). Thisproduces a narrow negative -going pulsetrain of 880 Hz which is presented toIC1b, a second D -type divide by two cir-cuit. This produces the 440 Hz referencewith a precise 50/50 mark space ratio. Q3and its associated components reduce thesignal to approximately line level and per-form wave shaping.

The power supply is a single 9V PP3battery connected via a simple SPSTswitch with decoupling performed by C7and C8. Current drain is typically 4mA.

The prototype was constructed on asmall printed circuit board in an ABS boxmeasuring 120 x 80x 30 mm. It should benoted that although the inputs to IC3 arearbitrary, the pin connections shown givethe simplest PC layout if the chips arepositioned side by side with the 4040 onthe left, pin 1 top right.

Finally, although the unit was design-ed to run from a 9V battery, it will runequally well on supplies of up to 18V suchas those found in many mixers and pre -amps although it is advisable to increasR2 and R7 accordingly.

+VE

1.111.4740.

VDD

loCBon-rI

11

+VE

DO2

22:51 53

IC2 4.7...11.13 10

11

2- 1 9Vcc 21'

9 12

2

1C3

1CDf

+VE

R4U'S

D 0

14 A 5 T"

NOTE.IC1 40131C2 . 4040IC3 406901,3.2N390402 . 2N39911%TALI 4.4330 MN:

IC1b 110

1St

IRS

03

+VE

11lig

4k7R

100k

O\

OUT

Slide Advance UnitBy Ian Lamb

THIS unit either encodes to or decodesfrom one channel of a stereo tape deck a1kHz tone to activate the remote advanceof a slide projector. The other channelutilised for commentary of the slide series.

When pin 2 is pulled low, either byclosing switch SW1 or by applying an

audio signal, the normally low output onpin 3 goes high, charging the capacitor onpin 6. This eventually causes pin 4 toswitch low, which pulls pin 1 low for aperiod of 3 seconds and pin 13 low for aperiod controlled by the setting of the100k potentiomenter. The output of thisgate (pin 11) pulsing high activates 1kHzoscillator for the recorder and providesbase drive to the Darlington pair con-nected across the remote jack of the slide

projector. The 100k potentiometer is ad-justed for the correct length of pulse toadvance the slide tray.

At the end of the 3 second period, pin1 is again high and if pin 2 has also return-ed high then the outputs on pin 3 goinglow discharges the capacitor on pin 6which in turn switches the output on pin 4to the a high, leaving the unit ready forthe next negative going input signal.

INPUT

SW1

DI

147k

jR44704

IC14

C310u

NOTE:ICI - CD409301 2142222A02 - BD13701,2 1N91403 1N4002

U0.

0+9v

/7M

°PROJECTOR

0 OV

0 RECORD


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Telecommunications Special!Includes MACDEM7, which isMODEM7 for the Macintosh;BASterm, a BASIC terminal programfor the IBM; a survey of availablemodems.

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Blort!A listing of video games for the 6502;check out some assembler techniquesor just blast at aliens.

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The Best From YourScope, Part 2More operating hints and tips on getting the bestperformance from the ubiquitous oscilloscope.

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Project

RS232 Breakout BoxHere's a handy projectfor all those computerhobbyists who've everwrestled with RS232cabling, 'sexing' andtroubleshooting.

By A. Bendili

RECENTLY, there have been a numberof articles describing troubleshooting aidsfor RS232 communication lines, e.g: Elec-tronics Today last month. There are alsocommercially available breakoutpanels/monitors suitable for use withRS232 equipment. These units invariablyrequire some form of external powereither via a battery set or plugpack. It isquite probable that, with infrequent use,the battery will be flat when you least ex-pect it, or you cannot get hold of a doubleadaptor or a long extension cable for yourplugpack.

The recent availability of high effi-ciency LEDs (e.g: National NSL 6752) haseliminated the power supply problem.These high efficiency LEDs typically emit40 mcd at 20 mA; as a result, only 2 mA isneeded to obtain the same light output asa standard LED driven with 20 mA.

DescriptionTo eliminate the power supply requir-ment, standard LEDs were not used sincethey would require at least 80 mA each.However, the high efficiency LEDsoperating at 1 mA emit adequate light toindicate whether the signal line ismark/space or disconnected but also toprovide reverse bias protection to eachother. The 2k7 series limiting resistor ishigh enough not to adversely load theRS232 lines and low enough so that theLED is still visible (albeit dim) with a 3 Vsignal through a 500 Ohm combined lineand line driver resistor. There is no circuitdefinition as to which end is the input oroutput. The input could logically be theside associated with the LEDs.

There are always two permanent con-nections to be made; these are the safetyground (pin 1) and signal ground (pin 7).Electronics Today January 1985

DB25 DB25PLUG SOCKET

RI

267

R2

267

jr LEW

.6/ LED2

ff LED3

L D4

0

6

20

R3

lj LEDS

-NA/V-2k7

R4

2k7

R5

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DB25SOCKET

DB25PLUG

0

Tx20 0 0

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6DSR 0- 0

RLSD 0 80

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DTR 0 0 O

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continued on page 52 45

By Roger Allan

RDI Video Disk Game

Electronics in ActionAn interactive videogame, a computerisedsorting machine, and awristwatch computer.

RDI Video Disk GameSOME years ago, someone had the brightidea of using video for arcade type games.The idea took hold and soon there werevideo arcades in practically every shopp-ing centre, much to innumerable parents'chagrin. More recently, there has been aslump in interest in such games. This ishardly surprising, as the quality of the im-ages is limited and rudimentary at best,and the games themselves are linear andpuerile in their banality. Even the lowestcommon denominator among us soonrealized that their repetitiveness was bor-ing.

One of the most successful of suchgames is known as "Dragon's Lair".Devised by Rick Dyer in California, itculled some $30 million in sales in its firstthree months. It is hardly surprising,therefore, that with the slump in arcadegame interest, and Dyer's abilities in thefield, that he should turn his attention tothe next generation of such games involv-ing interactive video disks.

The result, manufactured by RDIVideo Systems, is known as the "Hal-cyon". Essentially, it is a combination ofa computer and a laser -read video diskconnected to one's television. The result isreally quite extraordinary.

Like 'Dragon's Lair', the Halcyonsystem produces feature -movie qualityanimation or live action sequences tocreate a narrative world where the playermakes the choices for the characters and

the outcome is based on those decisions.In the course of the game, the playermakes dozens of choices among hundredsof possibilities from thousands of possiblecombinations with the outcome being dif-ferent each time that particular game isplayed.

The system employs artificial in-telligence, speech synthesis and voicerecognition to create a computerized per-sonality. It speaks in its own voice andrecognizes acquaintances by the sound oftheir voices, carries on rudimentary con-versations with them, and understandsand implements spoken commands. Bysimply speaking through a lightweightheadset, the player controls the actions ofthe characters in the game.

So far, RDI produces five adven-tures, "Thayer's Quest" (an historic fan-tasy adventure), "Orpheus" (an educa-tional Greek mythology adventure),"Shadow of the Stars" (a space explora-tion adventure), "Voyage to the NewWorld" (an historical adventure), and"The Spirit of the Whittier Mansion", ahorror adventure utilizing live actionrather than animation. As well, the systemcan run the 800 or so video disks availablefrom other manufacturers in standardLaser -format, as well as the new "B"music video disks.

More technically, according to Dyer,the system includes a 200 word vocabularywhich is expandable and is capable, vianetworking, of voice recognition of 200different peoples' voices, each one havinga vocabulary of 200 words. It essentiallyoperates on a voiceprint recognitionsystem, with the disk being the massstorage R/O unit, and the external Level 3computer providing the computationalfacility. Due to the artificial intelligenceaspect, the more the player interfaces withthe system over time, the more the

machine learns about you and the moreextensive is the development of its ownpersonality.

Due to its abilities, this system is alsobeing investigated by the Veterans Ad-ministration in the US for possible use byparaplegics. Due to the system's ability tolearn foreign languages, the system iscapable of learning the Vets' speech andundertaking actions on their behalf.

RDI Video Systems,2261 Cosmos Court,Palomar Airport Business Park,Carslbad, California,92008, USA


Electronically Sorted FruitWith the ever-growing world population,the cost of fresh fruit and vegetables, sonecessary for a healthy diet, tends to be aboom or bust situation. Either there is somuch of it, or not enough, and when thereis a lot, its quality tends to bounce all overthe spectrum. The major, non -farmingcost involved is not, surprisingly,transportation, but picking and sorting.

Recently, the French company,Materiel Arobriculture Fruitiere, com-menced marketing a machine whichsignificantly reduces the cost in the sortingstage of fruit by electronically dividing itaccording to its weight, diameter and col-our. It is a high capacity machineoperating 12 lines which check some 350buckets a minute, and identifies the cen-tral diameter of the fruit through ananalysis of its realtime image. The col-our -measuring sorting system determinesthe degree of the fruit's ripeness and sortsthem according to their different enddestinations, with the ripest being reserv-ed for the local market.

More specifically, one initially sets


the colour sorter by placing a well col-oured fruit under the initial sensor andtelling the terminal, via a keyboard, whatthe colour of the fruit is. The machinethen takes the incoming fruit load anddivides them into several groups of lanes(a maximum of four groupings) with everygroup working differently, eg. to dividethe size into two outputs or to put the se-cond quality on some specific lane, etc.

As the machine is running, amonochip microcomputer microprocessorsystem with a modular hierarchic struc-ture comes into play. Every sorting lane isdriven by a card using its ownmicroprocessor with a communal carddriving all the information exchanges bet-ween the lane cards, the colour sensorsand the operator at the terminal. In theevent of an error message, a software con-trolled system permits the operator tolocate the fault, both as to what the faultis and where the fault is located. Ad-justments may be made accordingly by theoperator without leaving the terminal andwhile the machine's non -fault lines con-tinue to run.

There are no optical elements, suchas incandescent lamps. As such there areno dust problem. By using amicroprocessor sensor, the machine per-

mits the analysis of almost the total sur-face of the fruit . thanks to four con-secutive readings from different angles.

For handling different fruits, themachine stores no less than eight differentprograms, each of which may be recalled

by the touch of a button, permitting easychange between crops. Further, new pro-grams may be entered while the machine isrunning on another program. For recordkeeping, the machine uses a standarddisplay terminal operating at 4800 baud,and a standard printer with a Centronicsinterface.

The machine received the Salon In-ternational du Machinisme Agricole 1984Gold Medal in industrial design.M. A . F.,(Materiel Arobriculture Fruitiere),546 Rue Gustave Jay,82000 Montauban,France


Seiko Data 2000Currently, watches seem to be goingthrough something akin to a metamor-phosis. No longer content to merely pre-sent time with sufficient accuracy to getone to the court to hear all sorts of awfulthings entered into testimony by one'ssoon -to -be ex-wife, watch manufacturershave extended their vistas to embrace thebriny deep or athletic events,includingpaper printouts, and have recently nudgedtheir commercial noses into the realm ofdata memory.

The top of the line in this latter for-mat is Seiko's Data 2000, a hybrid of agood watch and a mini -computer. Buteven the good people at Seiko have failedto overcome one difficulty: size. Hence itis in two parts, though the connection bet-ween the two is quite novel.

The first part looks a bit like anup-market watch, with all the appropriatefunctions. It has a I2 -hour display, withday, date and month, which automaticallyadjusts for all years other than leap years.It has a chronograph with simultaneoussplit and total elapsed time displays, andmeasures up to 10 hours in hours,minutes, seconds and 1/100 seconds. Italso has a display face, which can show an8 digit display in each of four lines.

Then the interesting bit. One may in-sert the back of the watch into a facepanel of what looks like a four functioncalculator with an alpha -numerickeyboard. Using the keyboard, one canenter up to 1000 characters in 100 linescontained in 2 separate memories. Assuch, one can enter all sorts of informa-tion: travel times, appointments,mathematical formula, business notes,memoranda, whatever. While connectedto the watch portion, one may access andmodify the information at any time, usinga fast forward and back continuous scrollreadout on the watch face.

The connection between the two por-tions is by low power radio transmission.In other words, the watch portion not on-ly has a miniature short range radiotransmitter, but a miniature receiver, as

WEDrESDE:inn

t u.U042

does the calculator portion. They operateon slightly different frequencies, such thatthey don't interfere with each other. Thekeyboard section, being larger, has thecircuitry to determine whether a messageis incoming from the watch, and adjustsinput/output accordingly. So minute isthe power consumption that the watchbattery will last for two years, and thekeyboard for five.

Seiko Time Canada,3900 Victoria Park A venue,Willowdale, Ontario,M2H 3P3, Canada



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ETI

Series

ConfigurationsIn this first of a newseries, we look at themultivibrator, composedof two discrete tran-sistors.

By Ian SinclairThe multivibrator is a circuit ofremarkable antiquity; it is attributed toAbrahams and Bloch at around 1918.Over the years, as various tube and subse-quently transistor versions were devised, avariety of names were attached to them.However, the names astable, monostableand bistable are particularly useful asdescriptions of the various multivibratorcircuits.

The astable is a circuit whichoscillates continually (no stable state -hence the name), producing steep -sidedwaveforms whose frequency can be ad-justed by changing RC time constants.The monostable has only one stable state,and an input pulse will disturb this statefor a time that depends on the time cons-tant of the circuit, following which itreturns to the stable waiting state. Thiscircuit is widely used as a pulse generator,because ideally the duration of the pulse(the pulse -width) is independent of therepetition rate of the pulse, which is deter-mined by the rate at which the monostableis triggered. The bistable circuit (twostable states) is the basis of digital cir:cuitry, but is seldom used in discrete formnowadays because of the low cost ofdigital ICs. A source of confusion overnames, incidentally, has been the use of'flip-flop' by digital circuit designers,whereas the name was traditionally usedto mean a monostable.

Astable AnticsTwo varieties of astable exist, the paralleland the serial, of which the parallel ismuch the better known. The basic circuitis shown in Fig. 1, but unless your needsare very simple, the waveform from this50

VCC

0.7C2 R3

DrilIVCC0.7C1.R2

IF C1.R2 = C2.R3 = CR

TIME OF WAVE = 1.4CR

FREOUENCY -1

OV1.4CR

Fig. I The simple multivibrator astable, with period formula.

circuit is not really good enough withoutreshaping. A much better circuit is shownin Fig. 2; this uses a diode to isolate thecollector from which the output is taken.When Q2 cuts off, its collector voltagecan rise sharply, leaving DI reverse bias-ed. In the simple circuit, a sharp rise ofvoltage at the collector of Q2 is madepossible by the capacitor C2 which has tobe charged through the collector loadresistor (R4 in Fig. 1). By using the diode,the collector voltage can rise sharply, andthe charging of C2 is done at a slower rateby the additional resistor R5. This ensuresa much sharper shape of waveform at theoutput.

Another problem of the simple cir-cuit is that, contrary to theory, its fre-quency changes as the supply is changed.This is because of silicon planar tran-sistors will conduct readily in the reversedirection when the base voltage is negativewith respect to the emitter (for an NPNtransistor). This is a form of zenerbreakdown, but it can be prevented byconnecting silicon diodes with a higher

reverse breakdown voltage in series withthe base leads, as shown in Fig. 3, sogreatly improving the frequency stabilityof the astable.

Formula For SuccessThe astable frequency is given by the for-mula shown in Fig. 1; it depends on thetwo sets of time constants. These shouldnot be greatly different; don't be temptedto try to produce pulses with very large orvery small values of mark -to -space ratioby using an astable with very differentvalues of the two time constants. Thewave form will probably be disappointing,and the circuit may not start oscillatingreliably.

The frequency stability of an astableis generally poor compared with that ofthe LC type of oscillator, and this featuremakes the astable particularly useful in-asmuch as it can be easily synchronised toexternal pulses. Unless the 'natural' fre-quency of the astable is reasonably closeto the incoming frequency, however, syn-chronisation cannot be relied on, and

+vcc

oV

Fig. 2 Using an isolating diode to sharpen the leading edge.Electronics Today January 1985

slowly -changing waves such as sinewavesare not useful for synchronisation becausethe triggering point is liable to vary (or jit-ter) from one wave to the next. Theastable can be synchronised by pulses atone base, and this can be done by pulsinga cut-off base into conduction or by puls-ing a conducting base to cut-off.

Fig. 3 Using base -isolating diodes to preventbase -emitter breakdown.

Whichever method is used, the trig-ger pulse should be isolated from theastable by diodes to prevent the astable in-terfering with the action of the trigger cir-cuit (Fig. 4). If the 'pulse -off' method isused, a catching diode must be included toprevent the transistor base -emitter junc-tion from being reverse -biased whichwould cause zener action of each negativepulse.

PULSE

la)

PULSE (OFF)-r(b)

Fig. 4 Diodes are used in the synchronising cir-cuits, too!

Breakfast Serial?The other type of astable, much less wellknown, is the serial astable, which is aparticularly good way of producing veryshort pulses which can pack a lot ofenergy. A circuit is shown in Fig. 5, andsince the circuit is not so familiar as thatof the parallel astable, a run through itsaction might be of interest. Note that onlyone time constant, RI.C1, is used, andthat the transistors are complementary;one PNP, one NPN.

We can start by supposing R2 = R3and Vcc= 10 V, with CI discharged so thatthe emitter of Q1 is at a low voltage. Q1will be cut off, and will stay that way untilits base voltage is more negative than itsemitter voltage, or to put it another way,until its emitter voltage fixed at ± 5 V byR2 and R3, the capacitor will have tocharge to around 5V6 before much willhappen.

Meantime, because Q1 cut off, nocurrent is reaching the base of Q2, andthis transistor also is cut off. The circuitremains with neither transistor conductinguntil the charging capacitor reaches thevoltage at which Q1 turns on. This alsoturns on Q2, because the collector currentof Q1 goes to the base of Q2. This in turndrastically lowers the base voltage of Q1,and the emitter voltage will follow it,rapidly discharging Cl. Once the emittervoltage of Q1 drops, however, the circuitrecovers, and we're back where westarted.

Fig. 5 The serial astable circuit using com-plementary transistors.

Unlike the parallel circuit, in whichone transistor conducts while the other iscut off, the serial multivibrator spendsmost of its life with both transistors cutoff, and only brief intervals with bothturned on. The cut-off time is the timeneeded to charge Cl through RI to aboutOV6 above the voltage supplied by R2 andR3 - the formula for the time is shown inFig. 5. The time for which both transistorsare on is less easy to estimate because itdepends on the effective resistance of thetransistors at saturation; it is normallyvery short compared to the charging time.

MonostablesThe classic monostable uses a parallel cir-cuit with one DC coupling, as shown inFig. 6. With no trigger -pulse input, Q2 isheld on because of current flowingthrough R2. The collector voltage of Q2 isvery low, and this ensures that Q1 is heldoff. This is the stable state of the circuit,and it will remain in this condition, withCl charged, until a positive -going trigger

Fig. 6 The parallel monostable circuit.

pulse arrives, withmake Ql conduct.rent to flow in Q1voltage drops, and

enough amplitude toThis pulse causes cur-, so that the collectorthe drop in voltage at

the base of Q2 cuts Q2 off. This conditionlasts until Cl charges through R2 suffi-ciently to turn the base of Q2 on again,when the circuit switches back. The diodein the base lead of Q2 prevents base -emitter breakdown from affecting thetiming.

As in all parallel circuits, there isalways one transistor conducting and theother cut off. The serial version of themonostable (Fig. 7) uses complementarytransistors, and will pass no current in itswaiting state. When a trigger pulse ar-rives, Q2 switches on, and the voltage atits collector drops. This switches on Q1,via the capacitor Cl, causing the base cir-cuit of Q2 to be heavily forward biased.Cl now charges through R2 until thevoltage at the base of Ql rises to its cut-off value of around VC -0V6. Both tran-sistors then cut off.

Fig. 7 A serial astable -a useful circuit whichis seldom seen.

The pulse width of the outputdepends on the time constant of CI .R2,and will vary as the supply voltage varies.Diodes can be used to prevent base -emitter breakdown in the usual way.

Bistables, Two By TwoFigure 8 shows the classic bistable circuitusing two NPN transistors. The circuit isstable with either Q1 on and Q2 off, or inthe alternate condition of Q1 off and Q2on. Switching is done by using the A or Binputs. With Q1 on, a negative pulse at Awill switch the circuit over, and a negativepulse at B will switch it back. This actioncorresponds to that of the simple set -resetlatch.

Counting action may be obtained ifsteering diodes are added to the basic cir-cuit, as illustrated in Fig. 9. Suppose Q1 isconducting: its base voltage will bearound OV6, and its collector voltageabout OV1, so that DI is almost conduc-ting. D2 is cut off because its anodevoltage will be about zero and its cathodevoltage almost at supply voltage. Cl willcarry virtually zero charge, while C2 willbe charged to around supply voltage, V.When a negative trigger pulse ofamplitude around 1 V is applied DI con-ducts, allowing Q1 to be cut off by thetrigger pulse; however, D2 is held off bythe charge on C2. The bistable thenchanges over so that Q2 is fully conduc-ting and QI cut off. In this condition, it isD2 which is biased almost on and DI com-


Configurations

pletely off. When the next trigger pulse ar-rives, then, Q2 will be cut off by it, andthe circuit will switch back to its originalstate. Hence, if the circuit is triggeredregularly, either output will be a squarewave with half the frequency of the triggerpulses.

The waveforms at the collectors of abistable can be much closer to square thanthose from simple astable, so that one wayof creating well shaped square waves is todrive a bistable from an astable (Fig. 10).In this circuit, the output from thebistable has the same frequency as theastable. Nowadays, the ready availabilityof bistables in integrated form discouragesus from using the discrete variety - we'lllook at IC types later in this series.

Fig. 8 The simple R -S type bistable.

continued from page 45

Fig. 9 A bistable with steering diodes to give the scale -of -two action.

ASTABLE

OUTPUTS

LF1J-

ru-L.

BISTABLE

INPUTS oOUTPUT

Fig. 10 Following an astable with a bistable to sharpen the waveform.

RS232 Breakout Box

The other pins usually depend on theusage, e.g: Tx and Rx could be reversed:some peripherals use RTS instead ofDTR.

A spare, unlabelled LED could beconnected to any of the 4 mm sockets tomonitor its status. I found that a set ofeight leads consisting of a flexible wireabout 100 mm long terminated at eachend with a stackable 4 mm plug is suffi-cient to link, stack, strap, crossover, pullup and monitor.

A double row of 4 mm sockets allowsthe connecting of input to output accor-ding to the situation in hand.

ConstructionAs shown in the accompanyingphotograph, the unit was built in a diecastbox. A connector pair consisting of a plugand socket on each side of the box allowsfor cables with either termination to beconnected to the breakout box. A labelbetween the two rows of sockets identifiesthe pin number and its conventionaldesignation. As it is highly unlikely thatall 21 RS232 signals will be monitored, theminimum set of signals shown on the cir-cuit diagram would be adequate for near-ly, if not all, situations.

0825 PLUG

D825 SOCKETREAR VIEW

REAR VIEW

LEDS 1.12 ANDR1-6 SIMILAR SAFETY GROUND

DB25 PLUGREAR VIEW

HOW IT WORKS

Back-to-back high efficiency LED pairs,LEDs 1-14, are connected across the RS232signal lines with a 2k7 current limitingresistor in series. The plug/socket pairs onthe left and right can be linked via the cen-tral column of sockets, the LEDs indicatingthe presence or absence of signal and itspolarity on the lines.

1ZraMEMResistors all 1/2W, 5%

R1-7 2k7Semiconductors

LED1-14 National NSL 6752 orsimilar

MiscellaneousDiecast box to suit; 16 x 4 mm 'banana'sockets; 1 x 'banana' socket -terminal; 2 xDB25 chassis -mount plugs; 2 x DB25chassis -mount sockets; 5 mm LED clips;hookup wire, etc.

52 ElectNnics Today January 1985

continued from page 21 Designer's Notebook

eight transistors, Fig. 4. This relies on thecharge stored at X during CK lows. WhenCK goes high the signal propogates to Q.Of course, the gate capacitance at X willleak, so a minimum clock frequency of afew kHz must be guaranteed.

Because transistors in the ULA areindividually accessible, composite gatescan be built up using less silicon area thanif a gate array really were an array ofgates, rather than transistors, Fig. 5.

Once initial design is completed,some verification of the design will be re-quired. At around -10,000 per fabrica-tion run, the 'suck -it -and -see' approach isnot popular. This is where CAD (Com-puter Aided Design) is used.

CK CK

Fig. 4 Faster, more economical D -type usingthe gate capcitance at point X as a storage ele-ment.

Verification ProcedureInitially electrical characteristics, usuallyjust propogation delay in logic design, arechecked. Most common elements, in-verters, AND gates, adders and so on will

AO

+VE

BO

ox

0 C

nil q 4 OD

EQUIVALENT TO

BV

Fig. 5 Composite gate, where the gate functionhas been implemented directly rather than beenbroken down into individual elements.

already have been simulated by themanufactuer, but a few special functionsmay require investigation.

COMPUTER ANDELECTRONICS

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To simulate a circuit at this level(device level) requires a program withdevice models incorporated, and aknowledge of the model parameters touse, things like channel length, oxidethickness and doping levels for verythorough simulations, or turn -on voltageand channel dimensions for more approximate simulations. The program takes itsinformation from a file containing the cir-cuit description, and a set of instructionson what to do to the circuit.

For propogation delay analysis, thecircuit is stimulated with a known inputwaveform, and the program instructed togive the input and output voltages at say,1 ns intervals. The output can be plottedby another part of the program and delaysread off, Fig. 6.

To simulate a whole circuit at devicelevel is possible, but rather pointless; thedetail is unnecessary and the program ex-ecution time too large. Other, circuit levelsimulators are employed, for which theparameters used are simply gate delays.The output from this simulation is used todetect hazards and glitches which may nothave been present in the breadboardmodel due to its different layout, logicfamily or size.

A hazard exists when different delay

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Designer's Notebook

1 1 1 1 1 I I I 1 1 1

1 1 I 1 1 I 1 1 1 1 1

I 1 1 1 I 1 1 I I I I I 1

1 1 1 1 1 1 1 1 1 1 I

1 1 1 1 1 1 1 1 1 I I 1 1

--1-4--+1 1 1 1 1 1 1 1 1 1 1

1 1 1 1 1 1 1 1 I 1

1 1 1 1 1 1 I 1 I 1 1

I 1 1 1 1 1 I I 1 1 1

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A 4 I A J

TIME tns)

paths in a circuit cause the output tochange state when it is not expected to.The output of Fig. 7 should be low onlywhen ABC = 011. A transition of ABCfrom 001 to 111 should therefore have noeffect on X - it will remain high.However it can be seen from the timingdiagram that if the AND and NAND gateshave different propogation delays as theyoften do in practice) there is an outputchange.

The presence of problems like thismay mean the difference between successand failure of a design. Hazards can beeliminated by careful design, or made ir-relevent by using fully synchronous(clocked) logic, essentially allowing thecircuit plenty of time to settle between in-put changes.

Another important factor a designermust consider is testability. An IC maycontain the equivalent of 2000 gates andyet have only 40 pins. It is not possible toput test probes inside an IC, as it is toosmall. Every test node must somehow bebrought out to a pin, or at least a bondingpad.

Getting StuckThe two most usual fault conditions in anIC are a gate input stuck at '1', and a gateinput stuck at '0'. Consider the circuit ofFig. 9. If this circuit operated correctly,then input ABC = 0 would produce theoutput X = 0. However, if B is stuck at 1the output will be 1. The patternABC = 100 is a test for the fault B S -A-1(B stuck at 1).

The problem in an integrated circuitis that the circuit of Fig. 8 may be 'buried'deep in the IC, and it is difficult to get therequired test patterns to it - perhapsother circuits have to go through severalstates before the values on ABC reach100. One rather elegant solution to thisproblem is called scan design.

Most logic circuits have flip-flops and

54

registers on them. By designing a fewmore and adding some extra steeringgates, the on -chip registers can be con-nected as a long shift register, and the lat-ches used to hold test patterns.

Three extra pins are needed: 'TEST',`TEST DATA IN' and 'TEST DATAOUT'. When TEST is high, the circuit isin test mode, and test data is serially fed into the flip-flop chain. After a number ofclock pulses the required test pattern is inthe circuit under test. TEST is taken lowand the circuit operated normally. Testoutputs are sent to the registers. ThenTEST goes high again and the outputvalues are clocked out along the shiftregister to TEST DATA OUT.

There are algorithms for finding testpatterns for the possible faults in a circuit.Given the logic diagram, corrects softwareand sometime, the computer can generatetest patterns for most faults. It can alsodetail those faults which are undetectablewith the circuit as it stands; such faultsoften indicate some redundancy in the cir-cuit.

The gate level simulator can be usedto simulate a faulty circuit. This may seemunnecessary, but is useful to test the effi-ciency of test patterns.

Fig. 7 An example of a liming hazard.

The LayoutThe next stage is the circuit layout. Thedesigner will probably start with a papersketch showing roughly where each func-tional block will go, and proceed fromthere. He or she will try to interconnectthe blocks along certain allowed lines(there will be a set of design rules, govern-ed by the accuracy of the manufacturingprocess, which determine track minimumwidths and spacings, etc). There areautomatic connection routing programs,but they are usually for two or moremetallisation layers, while most ULA'shave only one. People produce more com-pact layouts than computers, especially

when constricted to fixed channels allow-ing only a certain amount of interconnec-tion tracks.

Finally, automatically, semi-automatically, or manually, a layout isproduced. The likelihood of an error,especially with a manual layout, is high.

A piece of software called a designrule checker will look for tracks too closetogether, incomplete tracks and so on,reporting back to the designer, who canedit mistakes at an interactive graphicsterminal. There is also the question ofwhether the circuit drawn actually per-forms the intended function, even if itcomplies with the rules for physicallayout. A circuit extractor program canwork out the function of the layout,simulate it, and compare the resultsagainst those expected from the circuit.This is a difficult and time-consumingtask, even for a powerful computer. Theneed for this stage can be reduced bycareful design, or eliminated completelyby the use of automatic layout and inter-connection.

Finally the data describing the com-plete, checked layout are fed to anotherprogram which generates instructions fora machine which produces the metallisa-tion masks. Masks traditionally are madeby photographic reduction of 400X fullsize master, cut by a computer -controlledknife. Nowadays electron -beamlithography is common; an electron beamscans the actual size mask, exposingelectron -sensitive resist. This lattermethod is more accurate than the first,allowing higher circuit densities, and,because each chip pattern is individuallywritten, it costs little extra to change theprogram halfway and write two, three orfour different metallisation layouts ontoone mask. This allows smaller than usualquantities to be economically committed.

The FutureWhat of future developments? Mostpredictions are based on companyforecasts, and they obviously predict arosier future for whatever semi -custommethod or technology they are marketingthat their competitors do not have.However it is possible to say some thingswith reasonable certainty.

Silicon -gate CMOS arrays are likelyto dominate the market in most applica-tions, due to their combination of speed,density and low power. Low power densi-ty is important with high levels of integra-tion - chips which dissipate more than awatt or so require special packaging tokeep them cool and the package may costmore than the chip it houses.

Sofware is still chasing hardware insophistication - 20,000 gate arrays areannounced but no CAD system can ade-quately handle them yet. 30,000 gate ar-rays have been predicted for 1985. Array


manufacturers are becoming aware ofthese difficulties, and are employing soft-ware writers to produce product -specificCAD tools at the same time as hardwaredesigners work on the physical design ofthe array.

Most ULA sales are in the 300-1,000gate range, the very large arrays tending tobe purchased by the computer industry. Arecent FPLA chip (the AmPAL22V10from Advanced Micro Devices) claims tooffer the versatility of a 500 to 1,000 gatearray be of clever design and the provisionof over 5,800 fuses. Perhaps we shall seeFPLAs making headway into marketspreviously the domain of the gate array.

Fig. 8 Fault testing: suppose the input B isstuck at 1.

By the end of this decade CAD soft-ware may have advanced to the levelwhere the standard cell will exceed thegate array in popularity. This is becausemost systems are not composed only oflogic circuits - they contain RAM,ROM, EPROM and linear devices like op -amps, analogue to digital converters andvoltage references. There are arrays whichhave linear functions and memory areason them (an ordinary array wired as aRAM is very wasteful of silicon) but theproblem is always how much space toallocate to each function. If too manychoices are offered none will sell in largenumbers and the advantages of mass pro-duction are lost. With a standard cell ICthere are no such problems - as muchROM, etc, as is needed is fabricated.

Increasing levels of integration bringproblems of pinout too - 64 pins is theusual maximum in a DIL package.However a semi -custom IC may be replac-ing a whole PCB with over 80 connec-tions. We are likely to see more and moreexotic packages such as flatpacks and pin -grid arrays (which look like a bed of nailsfrom the pin side).

In conclusion, then, it seems likelythat more and more products will employsemi -custom ICs of one sort or another.These ICs will be designed by ordinary cir-cuit designers, using powerful softwaretools running on mini -computers orspecial-purpose micro -computers.


40ActiveYOUR ELECTRONIC COMPONENTS CENTER

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56 BCS Electronics Limited, 980 Alness St., Unit 7, Downsview, Ont. M3J 2S2 (416) 661.5585

Fixed Lead Oscillosco e Probes

Attenuation RatioBandwidthRise TimeInput Capacitance

Input Resistance

Maximum Input VoltageWorking Temperature RangeCable Length

1:1DC - 20 MHz17 nS55 p.F. + Oscilloscope InputCapacitance1 MD (Oscilloscope InputResistance)600 Volts DC Including peak AC-25 to +70°C1.5 Metres

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I

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10:1DC -100 MHz3.5 nSNominal 15 p.F.10-60 p.F.10 Mfg When used withoscilloscopes which have 1 MDInput. (Probe resistance 9 MD±1%)

Maximum Input Voltage 600 Volts DC Including peak AC,derating with frequency

Working Temperature Range -25 to +70°CCable Length 1.5 Metres

Also available with cable lengths of 2 & 3 metres, details on request.

BCS Electronics Limited, 980 Alness St., Unit 7, Downsview, Ont. M3J 2S2 (416) 661.5585 57

Review

ACNAPElectronic Circuit Analysis program

ACNAP is an AC electronic circuit analy-sis program written in Fortran, convertedto machine code, and available for over80 makes and models of microcomputers.It allows frequency response and phasemeasurements to be specified for anycombination of up to 60 resistors, capaci-tors, inductors, and current sources (gainstages). It doesn't require complex engi-neering practices to operate, though it'sassumed that you can manage simplemodels of amplifier circuits and can breakamplifiers down into voltage- controlledcurrent sources with input and outputimpedances in the right places (it's not asintimidating as it sounds).

After loading the program, you caneither load in a previously saved circuit totinker with it, or you can type in a newone. In the latter case, you'll see the mainmenu; its choices consist of functions likeload, save, list components, change com-ponents, run the circuit, noise equivalentbandwidth and so on.

Entering a CircuitComponents are entered by specifyinghow they relate to their neighbours; this inturn is done by calling each junction ofcomponents a node. If you're not familiarwith network theory, you'll soon get the58

ACNAPCircuit AnalysisProgram

Triumph over the number -crunchingrequired for networks and activefilter design with this circuitsoftware.

By Bill Markwick

hang of it; node 0 is always ground, node Iis always the input, and if you wanted toshow a 10K resistor from the input toground, for instance, you would enter:

R1: 10K+ node: 1-node: 0

An active filter is reprinted from themanual in Fig. 1, showing how the nodeswork. It's cumbersome at first, but it soonflows along, and it's the best way to dealwith components short of drawing the cir-cuit with a light pen. After entering nodes,the component tolerance is listed. Thesame procedure is followed for all passivecomponents; the final step is to specify theinput and output resistances as well as thegain of the amplifier stage, if any. A 0.0 istyped in if a particular type of component isnot in the circuit.

Testing and RunningOnce all desired values are in, you canreturn to the main menu and list them.This will be your first surprise: ACNAP'sone serious drawback is that it is veryfussy about number formatting. Integersmust look like 5.0 instead of 5, and prom-pts such as "number of nodes" must not,

or else the program sets your value to zeroin the first case or crashes in the second.

However, this was the only major prob-lem I encountered, and to be fair to thepublishers, they've included a form askingfor your opinion on how the software couldbe improved. To continue: once the valuesare to your liking, you can then run theprogram, specifying the bandwidth andnumber of sample points. After a few sec-onds, depending on how many samplepoints there are, you'll be presented withthe readout shown in Fig. 2, giving themagnitude in decibels and the phase anglein degrees.

One minor complaint was that there is noway to quickly find the centre frequency,which is usually what you want to checkright away just to make sure you didn't slipa digit and put your audio filter up in themegahertz region. One way to find it, I

discovered, was to watch for the generalfrequency of interest (in the example, itwould show as maximum gain, or mini-mum loss) and then re -run the circuit withlots of samples clustered around the area ofthe centre frequency. This allowed me tofind it within a fraction of a Hertz.

Monte CarloIf you're designing an uncritical circuitsuch as a simple lowpass, you'll probably


Fig. 1. The schematic of an active filter used as an ACNAP example.

be content with the expected variationsdue to component tolerances. However, ifyou're designing test gear, or very fussyactive filters, component variations maycause effects far more serious than thepercentage tolerance would indicate.ACNAP will "build" any number of cir-cuits by computing magnitude and phaseaccording to a random choice of compo-nent values within the specified toler-ance.

As an example of how valuable this canbe, I ran the test circuit shown for ten trieswith 5 percent components. The variationin magnitude at 1300 Hertz from circuit tocircuit was about 2.5 dB, not exactly pre-cision performance. At this point, youmight be tempted to stuff everything with.1 percent components, but there's a moreefficient way:

SensitivityReturn to the main menu, and you'll see"Compute Component Sensitivities".What you'll get is a list of magnitude andphase changes of the circuit over variousfrequencies as each component value isincreased by 1 percent. Some componentshave a negligible effect; some cause thecircuit performance to alter drastically.

Once you determine the culprit compo-nents, you can return to the main menuand change them to better tolerances andrerun the circuit, including the MonteCarlo.

Options and OthersACNAP itself doesn't support graphics,but BV Engineering have other compati-ble software to do the job: PLOTPRO is agraph printing program for ACNAP, andgenerates graphs on any 80 or 132 columnprinter. It provides linear, semi -log, orlogarithmic plots, including optional gridlines, and also labels anything on thegraph. It costs $49.95 US plus $8.60 forairmail to Canada.

Another companion program (whichwe didn't have as we went to press) is theSPP, or Signal Processing Program. Itgives the time domain response of theACNAP circuit for any input waveform; itlooks invaluable for transient response. Itcosts $59.95 US plus $8.60 for airmail toCanada.

MiscellaneousOnce the circuit data goes scrolling pastyou, there isn't any way to back up andreview it; however, there's a printer tog -

Frequency Magnitude (dB) Phase(Deg)

10.000 -60.643 -90.06319.953 -54.642 -90.12139.811 -48.636 -90.23879.433 -42.612 -90.471158.490 -36.517 -90.946316.229 -30.127 -91.970630.959 -22.379 -94.8051258.929 -2.112 -149.6562511.896 -21.250 95.4735011.893 -29.356 92.15210000.046 -35.815 91.025

<Enter 0 for main menu> 0

Fig. 2. A listing of the magnitude and phase response of the circuit in Fig. I.


gle so you can record how you're doing asyou change components.

We received ACNAP in the Apple 56KCP/M format; it occupied about 38K ofspace on the disk. Circuits were saved asnormal CP/M files, and could be trans-ferred or deleted as usual. ACNAP alsogenerated two other ASCII data files foreach circuit; these were for the companionprograms mentioned above.

Incidentally, you can also use the pro-gram for simple passive circuits as well; Idesigned a ladder attenuator by enteringall the resistors and then specifying thesame frequency for the minimum andmaximum. Out came the loss in dB. Ofcourse, you could always stick in a fewparallel capacitors to represent straycapacitance.

In conclusion, I have the feeling that ifI'd had ACNAP ten years ago, I couldhave saved an enormous amount of timewhen I was a circuit designer, and best ofall, I could have run lots of computersimulations for optimising the circuit.Unless you have an obsession for bread-boards and bits of wire, ACNAP is asuperb tool for circuit design.

For further information, contact: BV Engi-neering, PO Box 3351, Riverside, Cal.92519(714) 781-0252.

MULTI -LAB

$239.00 Kit $289.00 AssembledWant to simulate an industrial process?

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change during a process control.These interfaces can be accessedindividually, but are connected to acommon bus. This permits access toone or more interfaces during thesame process.

FREE!Call or write for your free cataloguefeaturing the products we manufacture.Add 3% shipping and handling. Quebec residents: add9% P.S.T. Cheque, money order, visa accepted. Pleaseprint your name visa no, expiration date & signature.

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continued from page 28 For Your Information

More Computer Care

Well, you say that you didn't savethat 12K Wordstar File after everyparagraph or so, and you've lostyour day's work? Dirty R/Wheads giving your grief? Wellthere's help on the way.

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Boeing Vertol Company hasawarded a $2.9 million contract toAtlantis Flight Research ofDownsview, Ontario, Canada.Atlantis will design and manufac-ture four maintenance trainersystems to help support BoeingVertol-built U.S. Navy and MarineCorps H-46 Sea Knighthelicopters.

During the 19 month contract,Atlantis will build two H-46hydraulic systems simulators andtwo Automatic Flight ControlSystem (AFCS) simulators. One ofeach will be used to trainNavy/Marine helicoptermaintenance technicians at therework facilities in New River,North Carolina and Tustin,California.

"This contract to AtlantisFlight Research represents ourcontinuing commitment to a pro-ductive relationship with the Cana-dian Aerospace Industry, one thatyields competitively priced, highquality components, systems andsubcontract work required to buildand support our helicopters," saidJoseph Mallen, president of Boe-ing Vertol. To date the Canadiandollar value of contracts awardedto 35 Canadian suppliers exceeds$170 million.

Torontel Technology SystemsLimited, a newly -formed Cana-dian company specializing in hightechnology information systemsand equipment, has been ap-pointed eastern distributor forRobot Research Inc. of San Diego,California - world's largestmanufacturer of phone -line videosystems. Victor Pacione, presi-dent, also announced that the com-pany will also design and manufac-ture custom systems forteleconferencing, tele-medicine,tele-education, security systemsand other sophisticated softwareapplication systems. "Our objec-tive is to provide business, govern-ment, industry and institutionswith the latest innovative informa-tion resources cost-effectively andefficiently. Our appointment asdistributor for Robot ResearchInc. and our internal resourcebase, provides Canadian organiza-tions with a single -source facilityfrom design through to installationand after -service", states Mr. Pa-cione. Torontel TechnologySystems Limited is located at: 205Riviera Drive, Markham, Ontario,(416) 475-9455.Circle No.54 on Reader Service Card

Further, we have yet to locate areliable source for the Power 3000computer, but we're still looking.

Shop Around Quality ProductsAnd all al s and Services

Compare Discount Prices*computer discount Mail Order Service AppleTM is a registered trademark of Apple Computers Inc. Now In Western Canada

*CD -80 PRINTER*

ONLY $36995

1111111114....: I.,- :.,.-

80 cps; 640 dots/line/sec; feed time ap-prox. 200 msec 04.23 mm; up to 142 col.(compressed print); Adjustable sprocketpin feed plus friction feed; Bi-directionalPrinter Parallel 1/F with printer . . . . $51.00CP-80 Cartridge $12.85

* DISK DRIVES*Shugart SA390 for Apple and Apple corn-patibles; full height; 40 tracks; 163K BYTES.One Year Warranty $249.95Chinon C.40 for Apple and Apple corn-patibles; slimline; direct drive; 40 tracks; ac-cess time 6 msec. 163K BYTES.One Year Warranty $254.95

Disk Drive 1/F with disk drive $46.00

* 6502 CASES*StandardWith numeric key pad

$29.95$39.95

Standard with key board $108.95Standard with n.k.p. in key board $128.95

*APPLE PERIPHERALS*Disk drive 1/F $ 49.95Printer 1/F w/cable $ 54.9580 col (manual) 1/F $ 74.9580 col (auto) 1/F $ 79.95Eprom writer (2716, 2732, 2764) S 68.20Z-80 soft CPM $ 51.75Buffer S 64.70Buffer 16K EX 64K $149.60Micro Buffer 32K $156.20Grappler $ 69.30Grappler/buffer 16K EX 64K $214.50Integer S 52.9016K RAM wlcable S 54.05128K RAM $236.5016K language S 60.50Speech S 55.00Music $ 69.30Clock $ 85.80RS 232S (serial) $ 49.50RS 232C (comm) S 63.80RS 232SS (super) $134.20Wild card $ 50.60

90 DAY WARRANTY

* KEYBOARDS *Standard $79.00With numeric key pad $139.00

*DISK DRIVE CASES*Slim horizontal $13.20Full height horizontal $16.501 Full or 2 slim vertical $19.25Dual slim horizontal $49.50

*MOTHERBOARDS*48K stuffed & tested $281.7564K stuffed & tested $322.00

* POWER SUPPLIES *Apple compatible $76.95

"Y" Power Cable D.D. $14.30 * ASSEMBLED UNITS*Case, Keyboard, Power Supply & SpeakerStandard S179.95With numeric key pad g197.95

*6502 MICROPROCESSOR*

.'f .1:i-,'.;: zi-....4

48K RAM; 8 expansion slots; Apple II com-patible; numeric keypad; 90 day war-ranty $3990064K RAM; 8 expansion slots; Apple II corn-patible; numeric keypad; 90 day war-ranty $44900

64K RAM kit 4164.15Ons; 9Memory Chips

$6400 or $750 each* DATA DISK BANKS*

store 50 disk

$1995

R.F. Modulation Kits WithoutSound $1495

Cooling Fan With Surge Protector$3048 * CLEANING KIT *

dry kit for cleaning disk driveheads $995

* DISKETTES*50 SS DD S 79.00

100 SS DD $150.00500 SS DD $719.00Prices include jackets, labels 8 write protecttabs.

Power Bar $1 840Apple II and Apple II +

Joysticks $2295IF WE DON'T LIST IT

ASK FOR ITCatalogues Available

For our U.S. Readers:P.O. Box 15485, Santa Ana, Calif. 92705

Call: 1-714-953-9105See our ad in BYTE for U.S. prices

dana's computer discountP.O. Box 6295, Station C

Edmonton, Alberta CanadaT5B 4K6 Tel: (403) 429-4718

We accept Certified Cheques, Money Orders, Bank Transfers,C.O.D.s, VISA and Mastercard. VISA and Mastercard add 3%.Cheques require bank clearance. All order shipped Freight Col -lect. All subject to availability, acceptance and verification.

All sales final. Prices subject to change without notice.Orders normally shipped within 48 hours of payment.

VISA

60Circle No. 2 on Reader Service Card Electronics Today January 1985

OSCILLOSCOPE HM 203-5

Coaxial test cable; length 1.15m, charac-teristic impedance 50 OHM, cable capacitance12pF. Input voltage max. 500Vp.

$10.40

Coaxial test cable; length 1.2m, characteristicimpedance 50 OHM, cable capacitance 126pF.Input voltage max. 500Vp,

$9.48

Two 4mm binding posts (19mm betweencenters) to standard BNC male plus. Inputvoltage max. 500Vp

$11.50

50 OHMp Through -Termination'

For terminating systems with 50 OHMcharacteristic impedance. Maximum load 2W.Max. voltage 10Vms.

For HM203-1 and HM203-3 HZ42For HM312, HM412, HM512,and HM705 HZ43

For HM307, HZ62,and HZ64 HZ44For HM103 HZ45

For HM203-5, HM 204and HM605 HZ46

$26.17

$66.00 20 MHz Standard Oscilloscope$48.00 Y: 2 channels, DC -20 MHz, max. sensitivity 2 mV/cm;

$39.00 X: 0.2s/cm -20 ns/cm incl. x10 magnification;$39.00 triggering up to 40MHz; Component Tester.

$73.50

For HM203, HM204, HM208, HM605, HM705,HM808, HM312, HM412, HM512, and HM812

$14.00 ea.

For checking the Y amplifier, timebase, andcompensation of all probes, the HZ60 providesa crystal -controlled, fast -rising (typ.3ns)square -wave generator with switchable fre-quencies of 1, 10, 100kHz, and 1MHz. ThreeBNC outputs provide signals of 25mVpp into 50OHM, 0.25Vpp (open circuit for 10X and 100Xprobes); accuracy ± 1%. Battery -powered orAC supply operated (optional). $63.75

Indispensable for trouble -shooting in elec-tronic circuits. Single component and in -

circuit tests are both possible. The HZ65operates with all scopes, which can be switch-ed to X -Y operation (ext. horizontal deflection).Non-destructive tests can be carried out onalmost all semiconductors, resistors,capacitors, and coils. Two sockets provide forquick testing of the 3 junction areas in anysmall power transistor. Other components areconnected by using 2 banana jacks. Test leadssupplied.

Examples of Test Display

LIST $75.00

The HM203 series is Western Europe's best-selling oscilloscope. Bothvertical amplifiers incorporate variable gain controls, and maximum inputsensitivity is 2 mV/cm over the full bandwidth of the oscilloscope. Anotherfeature permits display of the sum and difference of two signals.

Triggering facilities have also been expanded. In addition to line and TVtriggering, HF and DC triggering are possible. The HM 203-5 will trigger sta-bly with a 5 mm display height up to at least 40MHz. Using the manual levelcontrol, even relatively complex signals can be stably triggered. The timeresolution in horizontal direction is increased now, including x10 magnifica-tion, to max. 20 ns/cm

An 8 x10 cm internal graticule permits parallax -free viewing over awide angle. The effect of the earth's magnetic field upon horizontal trace posi-tion can be compensated for, externally, with a trace rotation control.

The HM 203-5 has a built-in Component Tester, which is especially usefulin maintenance and servicing work. Among other applications, this device ena-bles rapid in -circuit testing of semiconductors. Test voltage and current arerated so that normal semiconductors or other components cannot be dam-aged. Test results are displayed on the scope screen.

The HM 203-5 was designed for general purpose applications in industryand service. Its many operating modes, front panel layout, and ease of opera-tion also make it an ideal oscilloscope for use in training engineers and techni-cians.

SPAPPROVED $835.00

FST included

ELECTRONICSUMITED

980 Alness St. Unit 7,Downsview, Ontario

M3J 2S2(416) 661-5585

TELEX 065-28169Mon -Fri 8-5 pm, Sat 10 am -1 pm


BCS Electronics Limited, 980 Alness St., Unit 7, Downsview, Ont. M3J 2S2 (416) 661-5585 61

When we say don't drink and drive, we're not just talking about liquor.Twelve ozs. of beer, a 51/2 oz. glass of wine and 11/2 ozs. of spirits - they allcontain the same amount of alcohol. So they're all equally wrong to mix withdriving.

And, for that matter, just as wrong to abuse at any time.

P.O. Box 847, Stn. H, Montreal, Quebec H3G 2M8

SeagramWe believe in moderation and

we've been saying so since 1934.

XI 4 C lou Pri ter Plo terDraws clear Hi -ResGraphics, Charts, andText in 4 SelectableColoursTHIS IS A SAMPLE OFTHE NEW PL1 PLOTTERPRINTS TEXT IN ANYcase C upper & lower) andany

S I 3

llll UUMCOMMUUP"%NSW&KOIMMMIIMAMSIMIuun-

MMMM IMMEMEMMOMINISWIMIMMO

only

$249"model PL -1

Connects to any computer with Centronics(parallel) interface

Can be easily programmed for basic (corn-plete operating manual supplied)

Change colours instantly at any time Variable sized text, selectable from 1 to 80 col-

umns! Can print in 4 directions (e.g. upside down,

sideways, ect.)Includes 4 Long -Life colour plotting pens and1 roll of paper (4" width)

Gladstone Electronics is proud to introduce anew standard in printer plotters. The fine resolu-tion will amaze you. It can even print up to 80columns in a small but easily readable type for-mat. Print size is totally selectable in anynumber of characters per line, from 1 to 80.Uses standard paper (not thermal). The newPL -1 printer plotter from Gladstone Electronics.ETI loved it. You will too. Order today.

PSION ORGANISER $19995Price includes free 8K data pack and utility packAs reviewed in ETI December, 84, the world's first prac;tical pocket computer - (that actually fits in your pocket.

A unique Invention that will changethe way you work. Plug in EPROMS (electrially pro-grammable, read only

memories) which function as "disk" drives only 51/4" x 3" by 1" weighs only 8 oz. Save and recall up to 32K program/data using 2 16K Eproms Built-in database manager and a 16 character display with

full scrolling over each record up to 2000 characters long In stock software library Write/save your own programs Communications available with RS -232 link -up pack Programming language included in finance math, and

science packs Retains all data even when turned off or

battery is disconnected.

READY TO RUN SOFTWARE:

P21 Science Pack $ 79.95 P26 8K Datapak $ 34.95P22 Math Pack $ 79.95 P27 Formmater $119.95P23 Finance Pack $ 79.95 P28 Format Service 10.00P24 Link -up Pack $119.95 (lots more on the way!)P25 16K Datapak S 49.95

asfeatured

in ETI

STANDARD PARALLEL INTERFACES. If your computer does nothave a Centronics output, this chart indicates what you will needto order:

COMPUTER

C -64/V202068 TimexZX81/ TS1000Apple

Apple 2cMacintosh

CENTRONICS INTERFACE MODEL:Cardco G interface & cableCI -2068 interface & cableCI -1000 interface & cableor clone for II, II ±, IlePic card & cableModel 1 Granny Smith & cableModel 2 Granny Smith & cable

PRICE

$129.95$169.95$159.00

$124.95$199.95$219.95

Now available at Gladstone

SINCLAIR 01 $79995the mostsignificantcomputerlaunchof the 80's ..

32 -bit Processor, 128K Memory. Two built-in microdrives. High resolutioncolour. Includes software: word processing, database management,spread sheet & graphics.System Configuration. Basic system for $799.95 includes two processors,two custom -designed control chips, 128K main memory (expandable),operating system, programming language, full-size 65 -key QWERTYkeyboard, twin QL Microdrives (100K -byte capacity each with 3.5 secondsaverage access time), four software programs on Microdrive cassette (wordprocessing, spreadsheet, database management, graphics), four blankMicrodrive cassettes, power supply, connecting cables and adapters forTV, monitor and LAN.QL orders now being taken for deliveries to start in late January.As with all new SINCLAIR products we expect the initial demand to begreater than the supply available.Order now. All orders will be filled in sequence. Call toll free. Have yourcredit card number and expiry date ready. A $200.00 deposit will hold yourorder sequence, balance will be billed when shipment is made.If you prefer, mail you cheque for $200.00 with your order for C.O.D. balancewhen shipped.To save C.O.D. charges, send payment in full with a $5.00 shipping and in-surance.

Order toll free - have your credit card ready1-800-268-3640 (to place orders only)Product Information (416) 787-1448

GLAIDSTEME-1736 Avenue Rd.,

PHONE OR WRITEfor our new Glad-stone Electronicscatalogue.

NOTES ABOUT ORDERINGPersonal cheques must clear bank before shipment.CODs are accepted when accompanied by 20%deposit. Shipments are fully insured. Cost of in-surance and shipping is added on order - add 5% tocover estimated cost. ANY EXCESS WILL BECREDITED. Most orders are filled immediately.

LECTRIMICSToronto, Ontario M5M 3Y7

Our20th Year


Consider the new

est mem

ber of the Huntron

troubleshooting family.

The H

untron Tracker m

odel 2000 is a general purpose test instrument

which qualitatively evaluates digital, analog or hybrid sem

iconductordevices and reactive com

ponents. In -circuit or out -of -circuit tests may be

performed w

ith equal ease. NO

W quickly locate com

ponent failures insolid state circuits

..

.in -circuit, power -off. S

creen new parts to be sure

they will w

ork. Locate intermittents, shorts or leakage problem

s faster andeasier than you could ever im

agine possible. Many faults w

hich previouslyw

ere difficult or impossible to isolate w

ill be a thing of the past.

Contact us today for a dem

onstration and see what the

Huntron T

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oney.

CY

PR

US

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OD

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INC

.H

ead Office: 7648 H

eather St., V

ancouver, B.0

V6P

3R1

Telephone (604) 327-8814

Toronto O

ffice: (416) 666-3622 orO

ntario Toll -F

ree 1-800-263-2675

Circle N

o. 33 on Reader Service C

ard.

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