CHAPTER 2: DIGITAL ELECTRONICS WITH MULTISIM. edited by: engr noor badariah asan INTRODUCTION To...

CHAPTER 2:

DIGITAL ELECTRONICS WITH MULTISIM

edited by: engr noor badariah asan

INTRODUCTIONINTRODUCTION

To become familiar with Multisim – A computer program which simulates analog and digital circuits.

Multisim is a product made by Electronics Workbench (indeed, the program used to be simply called Electronics Workbench).

The program simulates analog and digital circuits. In this course, we will only use a few of the features available in

Multisim for digital circuits.

Comes with exceptionally easy to use schematic capture. Design entry is faster and more convenient. Components are grouped logically by device family for quick

access. No need to scroll through large library files searching for the part you need.

2


OverviewOverview

Electronics Workbench is used by industry for developing a broad range of products: Power Electronics Communications Consumer Electronics Robotics & Automation Test & Instrumentation Controls Biomedical

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Advantages of MultiSIMAdvantages of MultiSIM

Fast and easy schematic entry. Components are grouped logically by device family for

quick access.

4


Components can be dropped on a wire and Electronics Workbench automatically makes the connection.

To wire components together, simply drag from one connector to another connector.

You can route wires manually or turn on the “Auto-route” feature and the program routes wires for you.


5


Replacing a part with another member of the same device family is fast and simple.

Just double-click on the part and select the replacement.

Wires in EWB “auto-route” so that you can move components around the screen without breaking connections.


6


Simulator With EWB, you can change

component values while you simulate - no need to stop your simulation, make hangs, and then re-simulate.

Circuits can be tweaked and components can be changed faster and more easily with a simulator than they can be by hand calculation or on a lab bread-board.

High-Quality Model Electronics Workbench comes

with one of the largest component libraries.

Know exactly how your circuit behaves before you order components.

edited by: engr noor badariah asan 7

MultiSIM InterfaceMultiSIM Interface


Basic Elements:Basic Elements:

Multisim’s user interface consists of the following basic elements:

9


The system toolbar contains buttons for commonly-performed functions.

The Multisim Design Bar is an integral part of Multisim. The “In Use” list lists all the components used in the current

circuit, for easy re-use. The component toolbars contain Parts Bin buttons that let you

open component family toolbars. The circuit window is where you build your circuit designs. The database selector allows you to choose which database

levels are to be visible as component toolbars. The status line displays useful information about the current

operation and a description of the item the cursor is currently pointing to.

Basic Elements:Basic Elements:

10


The Design Bar is a central component of Multisim, allowing you easy access to the sophisticated functions offered by the program.

The Design Bar guides you through the logical steps of building, simulating, analyzing and, eventually, exporting your design.

Design BarDesign Bar

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Design BarDesign Bar

The Component Design Bar button is selected by default, since the first logical activity is toplace components on the circuit window.

The Component Editor Design Bar button lets you modify the components, or add components.

The Instruments Design Bar button lets you attach instruments to your circuit and see the results of your simulation on those instruments.

The Simulate Design Bar button lets you start, stop or pause the simulation of your circuit design.

The Analysis Design Bar button lets you choose the analysis you want to perform on your circuit.

The Postprocessor Design Bar button lets you perform further operations on the results of your simulation.

The VHDL/Verilog Design Bar button allows you to work with VHDL modeling (not available in all versions).

The Reports Design Bar button lets you print reports about your circuits (Bill of Materials, list of components, component details).

The Transfer Design Bar button lets you communicate with and export to other programs, such as Ultiboard, also from Electronics Workbench. You can also export simulation results to programs such as MathCAD and Excel.

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ComponentComponent

sources

basics

diodes

transistors

Analog ICs

Mixed ICs

Digital ICs

Digital Gates

Miscellaneous

controls

Indicators

Latches

13


SourcesSources

Ground Battery DC Current Source AC Voltage Source AC Current Source Voltage-Controlled Voltage Source Voltage-Controlled Current Source Current Controlled Voltage Source Current Controlled Current Source Vcc Source Vdd Source Clock AM Source FM Source

Voltage-Controlled Sine Wave Oscillator Voltage-Controlled Triangle Wave Oscillator Voltage-Controlled Square Wave Oscillator Controlled One-Shot Piecewise Linear Source Voltage-Controlled Piecewise Linear Source Frequency-Shift-Keying Source (FSK Source) Polynomial Source Nonlinear Dependent Source

BACK14


Connector Resistor Capacitor Inductor Transformer Relay Switch Time-Delay Switch Voltage-Controlled Switch Current-Controlled Switch Pull-up Resistor

Potentiometer Resistor Pack Voltage-Controlled Analog Switch Polarized Capacitor Variable Capacitor Variable Inductor Coreless Coil Magnetic Core Nonlinear Transformer

BasicsBasics

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DiodesDiodes

Diode Zener Diode LED Full Wave Bridge Rectifier Shockley Diode Silicon Controlled Rectifier Diac Triac

BACK16


NPN Transistor PNP Transistor N-Channel JFET P-Channel JFET 3-Terminal Depletion N-MOSFET 3-Terminal Depletion P-MOSFET 4-Terminal Depletion N-MOSFET

4-Terminal Depletion P-MOSFET 3-Terminal Enhanced N-MOSFET 3-Terminal Enhanced P-MOSFET 4-Terminal Enhanced N-MOSFET 4-Terminal Enhanced P-MOSFET N-Channel GaAsFET P-Channel GaAsFET

TransistorTransistor

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Analog and Mixed ICsAnalog and Mixed ICs

Analog ICs: 3-Terminal Opamp 5-Terminal Opamp 7-Terminal Opamp 9-Terminal Opamp Comparator Phase-Locked Loop

Mixed ICs: A-D Converter D-A Converter (I) D-A Converter (V) Monostable 555 Timer

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4000 (Dual 3-In NOR and INVERTER) 4001 (Quad 2-In NOR) 4002 (Dual 4-In NOR) 4008 (4-bit Binary Full Adder) 4009(Hex INVERTER) 4010(Hex BUFFER) 4011 (Quad 2-In NAND) 4012 (Dual 4-In NAND) 4013 (Dual D-type FF (+edge)) 4014 (8-bit Static Shift Reg) 4015 (Dual 4-bit Static Shift Reg) 4017 (5-stage Johnson Counter) 4019 (Quad 2-In MUX) 4023 (Tri 3-In NAND) 4024 (7-stage Binary Counter) 4025 (Tri 3-In NOR) 4027 (Dual JK FF (+edge, pre, clr)) 4028 (1-of-10 Dec) 4030 (Quad 2-In XOR ) 4040 (12-stage Binary Counter) 4041 (Quad True/Complement BUFFER) 4042 (Quad D-latch)

4043 (Quad RS latch w/3-state Out) 4044 (Quad RS latch w/3-state Out) 4049 (Hex INVERTER) 4050 (Hex BUFFER) 4066 (Quad Analog Switches) 4068 (8-In NAND) 4069 (Hex INVERTER) 4070 (Quad 2-In XOR) 4071 (Quad 2-In OR) 4072 (Dual 4-In OR) 4073 (Tri 3-In AND) 4075 (Tri 3-In OR) 4076 (Quad D-type Reg w/3-state Out) 4077 (Quad 2-In XNOR) 4078 (8-In NOR) 4081 (Quad 2-In AND) 4082 (Dual 4-In AND) 4085 (Dual 2-Wide 2-In AND-OR-INVERTER) 4086 (4-Wide 2-In AND-OR-INVERTER) 4093 (Quad 2-In NAND (Schmitt)) 4502 (Strobe hex INVERTER) 4503 (Tri-state hex BUFFER w/Strobe)

Digital ICsDigital ICs

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4508 (Dual 4-bit latch) 4510 (BCD up/down Counter) 4511(BCD to Seven-Segment latch/Dec) 4512 (8-In MUX w/3-state Out) 4514 (1-of-16 Dec/DEMUX w/Input latches) 4515 (1-of-16 Dec/DEMUX w/Input latches) 4516 (Binary up/down Counter) 4518 (Dual BCD Counter) 4520 (Dual Binary Counter) 4532 (8-bit priority Enc) 4556 (Dual 1-of-4 Dec/DEMUX) 40106 (Hex INVERTER (Schmitt)) 7400 (Quad 2-In NAND) 7402 (Quad 2-In NOR) 7403 (Quad 2-In NAND (LS-OC)) 7404 (Hex INVERTER) 7405 (Hex INVERTER (LS-OC)) 7406 (Hex INVERTER (HC-OD)) 7407 (Hex BUFFER (HC-OD)) 7408 (Quad 2-In AND) 7409 (Quad 2-In AND (LS-OC)) 7410 (Tri 3-In NAND)

7411 (Tri 3-In AND) 7412 (Tri 3-In NAND (LS-OC)) 7414 (Hex INVERTER (Schmitt)) 7416 (Hex INVERTER (HC-OD)) 7417 (Hex BUFFER (HC-OD)) 7420 (Dual 4-In NAND) 7421 (Dual 4-In AND) 7422 (Dual 4-In NAND (LS-OC)) 7425 (Dual 4-In NOR w/Strobe) 7426 (Quad 2-In NAND) 7427 (Tri 3-In NOR) 7428 (Quad 2-In NOR) 7430 (8-In NAND) 7432 (Quad 2-In OR) 7433 (Quad 2-In NOR (LS-OC)) 7437 (Quad 2-In NAND) 7439 (Quad 2-In NAND (LS-OC)) 7438 (Quad 2-In NAND (LS-OC)) 7440 (Dual 4-In NAND) 7442 (4-BCD to 10-Decimal Dec) 7445 (BCD-to-Decimal Dec) 7447 (BCD-to-Seven-Segment Dec)


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7451 (AND-OR-INVERTER) 7454 (4-wide AND-OR-INVERTER) 7455 (2-wide 4-In AND-OR-INVERTER) 7469 (Dual 4-bit Binary Counter) 7472 (AND-gated JK MS-SLV FF (pre, clr)) 7473 (Dual JK FF (clr)) 7474 (Dual D-type FF (pre, clr)) 7475 (4-bit Bistable Latches) 7476 (Dual JK FF (pre, clr)) 7477 (4-bit Bistable Latches) 7478 (Dual JK FF (pre,com clk&clr)) 7486 (Quad 2-In XOR) 7490 (Decade Counter) 7491 (8-bit Shift Reg) 7492 (Divide-by-twelve Counter) 7493 (4-bit Binary Counter) 74107 (Dual JK FF(clr)) 74109 (Dual JK' FF(+edge, pre, clr)) 74112 (Dual JK FF(-edge, pre, clr)) 74113 (Dual JK MS-SLV FF (-edge, pre)) 74114 (Dual JK FF (-edge, pre, com clk & clr)) 74116 (Dual 4-bit latches (clr))

74125 (Quad bus BUFFER w/3-state Out) 74126 (Quad bus BUFFER w/3-state Out) 74132 (Quad 2-In NAND (Schmitt)) 74133 (13-In NAND) 74134 (12-In NAND w/3-state Out) 74138 (3-to-8 Dec) 74139 (Dual 2-to-4 Dec/DEMUX) 74145 (BCD-to-Decimal Dec) 74147 (10-to-4 Priority Enc) 74148 (8-to-3 Priority Enc) 74150 (1-of-16 Data Sel/MUX) 74151 (1-of-8 Data Sel/MUX) 74153 (Dual 4-to-1 Data Sel/MUX) 74154 (4-to-16 Dec/DEMUX) 74155 (Dual 2-to-4 Dec/DEMUX) 74156 (Dual 2-to-4 Dec/DEMUX (LS-OC)) 74157 (Quad 2-to-1 Data Sel/MUX) 74158 (Quad 2-to-1 Data Sel/MUX) 74159 (4-to-16 Dec/DEMUX (LS-OC)) 74160 (Sync 4-bit Decade Counter (clr)) 74162 (Sync 4-bit Decade Counter) 74163 (Sync 4-bit Binary Counter)


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74164 (8-bit Parallel-Out Serial Shift Reg) 74165 (Parallel-load 8-bit Shift Reg) 74166 (Parallel-load 8-bit Shift Reg) 74169 (Sync 4-bit up/down Binary Counter) 74173 (4-bit D-type Reg w/3-state Out) 74174 (Hex D-type FF (clr)) 74175 (Quad D-type FF (clr)) 74181 (Alu/Function Generator) 74190 (Sync BCD up/down Counter) 74191 (Sync 4-bit up/down Counter) 74192 (Sync BCD up/down Counter) 74194 (4-bit Bidirectional Univ. Shift Reg) 74195 (4-bit Parallel-Access Shift Reg) 74198 (8-bit Shift Reg (shl/shr ctrl)) 74199 (8-bit Shift Reg (sh/ld ctrl)) 74238 (3-to-8 line Dec/DEMUX) 74240 (Octal BUFFER w/3-state Out) 74241 (Octal BUFFER w/3-state Out) 74244 (Octal BUFFER w/3-state Out) 74251 (Data Sel/MUX w/3-state Out) 74253 (Dual 4-to-1 Data Sel/MUX w/3-state Out) 74257 (Quad 2-to-1 line Data Sel/MUX) 74258 (Quad 2-to-1 line Data Sel/MUX) 74266 (Quad 2-In XNOR (LS-OC))

74273 (Octal D-type FF) 74279 (Quad SR latches) 74280 (9-bit odd/even parity generator/checker) 74290 (Decade Counter) 74293 (4-bit Binary Counter)) 74298 (Quad 2-In MUX) 74350 (4-bit Shifter w/3-state Out) 74352 (Dual 4-to-1 Data Sel/MUX) 74353 (Dual 4-to-1 Data Sel/MUX w/3-state Out) 74365 (Hex Bus Driver w/3-state Out) 74367 (Hex Bus Driver w/3-state Out) 74368 (Hex Bus Driver w/3-state Out) 74373 (Octal D-type Transparent Latches) 74374 (Octal D-type FF (+edge)) 74375 (4-bit Bistable Latches) 74377 (Octal D-type FF w/en) 74378 (Hex D-type FF w/en) 74379 (Quad D-type FF w/en) 74393 (Dual 4-bit Binary Counter) 74395 (4-bit Cascadable Shift Reg w/3-state Out) 74445 (BCD-to-Decimal Dec) 74465 (Octal BUFFER w/3-state Out) 74466 (Octal BUFFER w/3-state Out)


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2-Input AND Gate 2-Input OR Gate NOT Gate 2-Input NOR Gate 2-Input NAND Gate 2-Input XOR Gate 2-Input XNOR Gate Tristate Buffer Buffers

Schmitt Trigger AND Gates OR Gates NAND Gates NOR Gates NOT Gates XOR Gates XNOR Gates

Digital GatesDigital Gates

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Half Adder Full Adder RS Flip-Flop JK Flip-Flop with Active High Asynchronous Inputs JK Flip-Flop with Active Low Asynchronous Inputs D Flip-Flop with Active Low Asynchronous Inputs Multiplexer ICs Demultiplexer ICs Encoder ICs Arithmetic ICs Counter ICs Shift Register ICs Flip-Flops ICs

LatchesLatches

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Voltmeter Ammeter Bulb Probe 7-Segment Display Decoded 7 Segment Display Buzzer Bargraph Display Decoded Bargraph Display

IndicatorsIndicators

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Voltage Differentiator Voltage Integrator Voltage Gain Block Transfer Function Block Multiplier Three-Way Voltage Summer Divider Voltage Limiter Voltage-Controlled Limiter Current Limiter Block Voltage Hysteresis Voltage Slew Rate

ControlsControls

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MiscellaneousMiscellaneous

Fuse Write Data Lossy Transmission Lossless Transmission Crystal DC Motor Triode Vacuum

Boost Converter Buck Converter Buck-Boost Converter Textbox Title Block Netlist Component

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InstrumentsInstruments

Instruments are accessed through the Instruments button on the Design Bar. When you clickthis button, the Instruments toolbar appears. It includes one button for each instrument.

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Oscilloscope Oscilloscope

The dual-trace oscilloscope supports internal or external triggering on the positive or negative edge.

The time base is adjustable from 0.1ns to 1 s, with a voltage resolution of 10 uV to 5 kV per division.


Add Instrument


OscilloscopeOscilloscope

Colored graphs on the scope correspond to the same colored connections to the circuit. Note how the display changes as the scales are altered with the cursor.

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Logic AnalyzerLogic Analyzer

The Logic Analyzer can be triggered internally or externally on either the negative or positive edge, or by recognition of a predefined bit pattern.

It is used for fast data acquisition of logic states and advanced timing analysis.


Function GeneratorFunction Generator

The Function Generator produces square, triangular and sinusoidal waves.

You can control the frequency, duty cycle, amplitude and DC offset.


MultimeterMultimeter

The autoranging multimeter measures AC and DC current and voltage, resistance, and decibel loss.

The internal resistance and current can be easily defined.


Word GeneratorWord Generator

The Word Generator can drive a circuit by producing streams of 16-bit words.

It can be configured to step one word at a time, burst through user-defined sets of data, or cycle continuously at a specified frequency.


Bode PlotterBode Plotter

The bode plotter produces a graph of a circuit’s phase or gain with respect to frequency.

Useful for analyzing frequency response for all types of circuits.


BUILDING A CIRCUITBUILDING A CIRCUIT


Drawing a basic schematic circuit

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1.0: Placing Component on Circuit Window1.0: Placing Component on Circuit Window The component toolbar:

Placing your cursor onone of these Parts Bin buttons displays another toolbar, the component family toolbar, containing buttons representing the component families contained in that Parts Bin.

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1.1: Placing the First Component1.1: Placing the First Component

1) Place the cursor on the Sources Parts Bin button (or click it).

2) The contents of the Sources family toolbar appear.

3) Click the DC Voltage Source button.

4) Move to the circuit window, where we want to place the battery.

5) Click in this general area or, use the page borders as a guide and click in the intersection of row A and column 1. The battery appears on your circuit window.

Step 1: Placing a 5V Battery

39


1) To change the battery’s value, Double-click on the battery. The battery’s properties screen appears, with the Value tab displayed.

2) Change the “12” to a “5” and click OK.

Step 2: Change the Battery Value

To save your changes, choose File/Save As, and give a name (and location) for your circuitfile.

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1.2: Placing the Next Components1.2: Placing the Next ComponentsStep 1: Place a Resistor

1) Place your cursor on the Basic Parts Bin button and, from the toolbar that appears, click the Resistor button.

2) The resistor’s Browser screen appears.3) This Browser screen appears because the

Resistor family contains multiple real components that you could actually purchase.

4) Scroll through the Component List to find the 470ohm resistor. Select the 470ohm

resistor and click OK.5) To rotate the resistor, Right-click on the

resistor. A pop-up menu appears. Choose 90CounterCW from the menu.

6) You can move the labels that accompany a component’s symbol. In particular, you may want to do this after some rotations, if the labels are displayed other than as you prefer.

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Step 3: Add Other Resistors

1) To add the other resistors, add a 120ohm resistor at the intersection.

2) Notice how this second resistor is given the reference ID “R2”, to indicate it is the second resistor placed.

3) Place the third resistor, a 470ohm (you could use the “In Use” list for this if you wish), at roughly the intersection in window, and rotate it.

4) At the “In Use” list, just to the right of the Design Bar. It lists all the components you have placed so far. You can easily re-use a component from this list by clicking on it.

5) To move components to the desired location, simply single-click the component to select it

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The process of placing other components and creating a circuit diagram consists of selecting and dragging the components from a parts bin and connecting the components using wire.

For example, LED is from the diodes family, BJT_NPN is from the Transistor group, capacitor is from the basic group, a ground is from the sources group, and VCC is also from the sources group.

For a quick way to move components into line, select them and use the arrow keys on your keyboard to move the components in grid increments. Lining them up will make wiring easier.

1.3: Placing Other Components1.3: Placing Other Components

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1.4: Wiring Component1.4: Wiring Component

In MultiSIM, you can choose to wire components either automatically or manually.

Automatic wiring avoids wiring through other components or overlapping wires. Manual wiring means you control the path of the wire on the circuit window.

To start the wiring process:

1. Click the pin coming out of the bottom of V1.

2. Click the pin on the top of the ground. The two components automatically become wired together.

3. To stop the wiring process, press ESC.

4. To delete a wire, right-click on it and choose Delete from the pop-up menu, or press DELETE.

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To change the label of any individual component you have placed:

1. Double-click on the component. The component’s properties screen appears.

2. Click the Label tab and enter or modify the label (which must be composed of letters or numbers only—no special characters or spaces).

3. To cancel changes, click Cancel. To save click OK.

To change the color of any individual component, right-click on it and choose Color from the pop-up menu. Choose the desired color from the screen that appears.

1.5: Changing Label and Color of Individual Components and Nodes

1.5: Changing Label and Color of Individual Components and Nodes

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To add a title block, choose Edit/Set Title Block. Enter the desired title block text in the field and click OK. The title block appears at the bottom right of the circuit window.

To add text:

1. Choose Edit/Place Text.2. Click anywhere on the circuit window. A text box appears.3. Type the text—for example, type “My tutorial circuit”.4. Click on the location on the circuit window where you want the text placed. The mouse

was clicked at these points.5. To delete text, right-click on the text box and choose Delete from the pop-up menu or

press DELETE.6. To change the color of text, right-click on the text box, choose Color from the pop-up

menu, and choose the desired color.7. To edit text, double-click on the text box and make your changes. Click any location

out of the text box to stop editing text.8. To move text, click on the text box and drag it to a new location.

1.6: Adding Text to the Circuit1.6: Adding Text to the Circuit

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1.6: Adding Instrument to the Circuit1.6: Adding Instrument to the Circuit To add instruments, Click the

Instruments button in the Design Bar. The Instruments toolbar appears.

Click the desired instruments (e.x: oscilloscope), the desired instrument icon will appears in the circuit window and we need to wire the instrument with a correct terminal into the circuit.

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1.6: Simulating the Circuit1.6: Simulating the Circuit

To simulate the circuit, click the Simulate button in the Design Bar. From the pop-up menu, choose Run/Stop.

To stop the simulation, click the Simulate Design Bar button. From the pop-up menu, choose Run/Stop again.

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DC Operating Point Transient AC Frequency Sweep Fourier Noise Distortion Temperature Sweep

Parameter Sweep AC & DC Sensitivity Pole-Zero Transfer Function DC Sweep Worst Case Monte Carlo

Analyzing the CircuitAnalyzing the Circuit

Analysis functions in MultiSIM lets user investigate the circuit. Enable the user to understand circuit behavior and optimizing or correcting the circuit’s functionality.

To initiate the analysis, click the Analysis button from the Design Bar and choose the desired analysis from the pop-up menu.

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Digital Electronics with MultiSIM

Introduction to Digital Concepts


Concept of digital circuit

In electronics world there are 2 types of circuit: Analog circuit Digital circuit

Digital circuits referred to circuits that deal only in highs and lows with discrete binary values.

DIGITAL – only ‘0’ and ‘1’.

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Analog and Digital Circuit

V112V 50Hz 0Deg

V212V

X112V_25W

X2

12V_25W 1.463 A

+-

2.069 A+ -

52


Digital Waveform

V1 500Hz 5V

U1A

7432N

1

2

3

X1

2.5 V

A BT

G

XSC1

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Boolean Algebra – AND, OR, and NOT Function Boolean Algebra has become the preferred method of specifying

the logic or digital circuits. All logic functions, no matter how complex, that are required in

digital logic can be created from three basic logic functions: AND, OR and NOT.

The Boolean Algebra variables are the logic inputs to the logic gates and functions or of even more complex logic circuits.

The more complex gates, such as NAND or NOR can be thought of as at the bottom level as various combinations of AND, OR and NOT gates.

54


Logic Gates and Combinational Circuits Basic logic gates:

Inverter or NOT gate OR gate AND gate NAND gate NOR gate

Advanced Logic Gate: XOR XNOR

55


INVERTER/NOT GATE

S1

Key = Space

V1

5V

R1

1kOhm

U4

NOT

4.500 V+

- 5.000p V

+

-

1

0

2

3

A Y

0 1

1 0

56


INVERTER CIRCUIT USING IC TTL 7404 HEX INVERTER

V1

5V

S1

Key = Space

R1

1kohm

XMM1U1A

7404N

21U1B

7404N

43

U1C

7404N

65U1D

7404N

89U1E

7404N

1011U1F

7404N

1213

X1 X3 X2

X5 X4 X7 X6

57


INVERTER CIRCUIT

V1120V Y

A'

R1

100ohm

YCBA

58


OR Gate

S1

Key = A

U1A

7432N

1

23

V1

1000Hz 5V

R1

1kOhm

A BT

G

XSC1

High

LowV2

5V

INPUT A

INPUT B

OUTPUT, Y

0 0 0

0 1 1

1 0 1

1 1 1

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R1

1kOhm

V1

5V

S1

Key = B

U2A

7432N

1

23

U2B

7432N

4

56

S2

Key = C

S3

Key = D

U2C

7432N

9

108

S4

Key = A

S6 Key = E

U2D

7432N

12

1311

X1

OR CIRCUIT USING IC TTL 7432

5 INPUT OR GATE

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AND GATE

QC T

1

F

XLA1

A BT

G

XSC1

V1 500Hz 5V

V25V

U1A

74LS08J

1

23

A B Y

0 0 0

0 1 0

1 0 0

1 1 1

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AND GATE USING TTL 7408 IC

R1

1kOhm

S1

Key = A

V1

5V

S2

Key = B

U1A

7408J

1

23

U1B

7408J

4

56

S3 Key = C

U1C

7408J

9

108

U1D

7408J

12

1311

S4 Key = D

S5 Key = E

X1 X2 X3 X4

5 INPUT AND GATE

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AND and OR CIRCUIT

V112V

Y

A B C

AND CIRCUIT

A .B = Y

V112V Y

A

B

C

OR CIRCUIT

A + B = Y

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NAND GATE

A B Y

0 0 1

0 1 1

1 0 1

1 1 0Input B

Input AU1

R1 10kOhm

Output Y

V1

5V

S1

Key = B

S2

Key = A

X1

7400 NAND GATE

Key point for NAND:i) Output for NAND gate invert

output AND gate

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NOR GATE

V1

5V

R1 10kohm

X1

U1A

7428N

2

31

U1B

7428N

5

64

U1C

7428N

8

910

U1D

7428N

11

1213

U3A

7428N

2

31

J1

Key = A

J3

Key = B

J2

Key = C

J5

Key = D

5VVCC

X3

X2

A B Y

0 0 1

0 1 0

1 0 0

1 1 0

4 INPUT NOR GATE USING TTL7428

Key point for NOR:i) Output for NOR gate invert

output OR gate

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ADVANCED LOGIC CIRCUIT

The Exclusive-OR (XOR) gate The Exclusive-NOR (XNOR) gate

Inside the integrated circuits, these two exclusive gates consist of various combinations of the basic logic gates that are necessary to perform the required tasks.

66


XOR LOGIC CIRCUIT

4030BD

1

2

3

U1A

23

4009BCL

U2A

45

4009BCL

U2B

U3A

4081BD

1

23

U3B

4081BD

5

64

U4A

7432N

1

2

3

AB

Y

A

B

A'

B'

Y

Two-Input XOR Truth Table for A B = Y

A B Y

0 0 0

0 1 1

1 0 1

1 1 0

XOR Truth Table

A B = Y

Key point for XOR:i) Two inputs are same, output = 0ii) Two inputs are different, output = 1

67


XOR CIRCUIT USING TTL 7486 IC

R1

1kohmV1

5V

7486N

1

23

U1A

7486N

4

56

U1B

7486N

9

108

U1C

7486N

12

1311

U1D

J1

Key = A

J3

Key = B

X1

68


XNOR LOGIC CIRCUIT23

4009BCL

U2A

45

4009BCL

U2B

U3A

4081BD

1

23

U3B

4081BD

5

64

A

B

A'

B'

Y

U5A

74HC02N

2

31

U1

ENOR2

A

BY

Two-Input XNOR Truth Table

A B Y

0 0 1

0 1 0

1 0 0

1 1 1

Table 3-3 XNOR Truth Table

YBA Key point for XNOR:i) Two inputs are same, output = 1ii) Two inputs are different, output = 0

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R1

1kohm

V1

5V

U2

ENOR2

X1

J1

Key = A

J2

Key = B

XNOR CIRCUIT USING 74LS266N

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Rules of Boolean Algebra

Boolean algebra for expressing the relationship between a logic circuit’s inputs and outputs.

1) A + 0 = A

2) A + 1 = 1

3) A . 0 = 0

4) A . 1 = A

5) A + A = A

6) A + A’ = 1

7) A . A = A

8) A . A’ = 0

9) A’’ = A

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Demorgan’s Theorem

Demorgan’s theorm gives a procedure for complementing a complex function.

This theorem indicates and interesting relationship between NOR, OR, NAND and AND.

YXYX YXYX

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UNIVERSAL NAND GATE

NAND gates can be used to implement NOT, AND & OR gates.

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UNIVERSAL NOR GATE

NOR gates can be used to implement NOT, AND & OR gates.

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UNIVERSAL GATE NAND AND NOR

V1

5V

R1

1kOhm

R2

1kOhm

U1

AND2U2A

7400N

1

23

U2B

7400N

4

56

A

BY2

Y1

X1

X2

J1

Key = A

J2

Key = B

Universal NAND as AND gate

V1

5V

5V

VCC

R1

1kohm

R3

1kohm

S1

Key = AS3

Key = B

U1

AND2U3A

7402N

2

31

U3B

7402N

5

64

U3C

7402N

8

910

AB Y1

Y2

X1

X3

Universal NOR as AND gate

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Example 1: Representing OR gate with 2-input NAND gate.

BAY

BAY

BAY

Figure: Replacing OR gate with NAND gates

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Example 2: Representing AND gate with 2 input NAND gate.

BAY

BAY

Figure: Replacing an AND gate with NAND gates

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Example 3: Representing a NOR gate with 2 input NAND gate.

BAY

BAY

BAY

Figure 2.21: Replacing a NOR gate with AND gate

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1) From a Boolean Expression to a Logic Circuit

Eg: X = AB + C (Boolean expression)


Implementing Combinational Circuit

Logic circuit

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Implementing Combinational Circuit 2) From a Truth Table to a Logic Circuit

Eg: A B C Output, X Product Term

0 0 0 0

0 0 1 0

0 1 0 0

0 1 1 1 A’BC

1 0 0 1 AB’C’

1 0 1 0

1 1 0 0

1 1 1 0

Truth Table

Logic circuit?

- Get the Boolean exp:

X = A’BC + AB’C’

- Draw logic circuit

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Answer: X = A’BC + AB’C’ Logic circuit:


Implementing Combinational Circuit

U1A

7404N

21

U1B7404N

43

U1C7404N

65

1

2

8

9

U2A

4073BD

3

4

5

6

U2B

4073BD

U3A

74HC32N

1

2

3

A

B

C

X

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Combinational Circuit

U1A

7408J

1

23

U1B

7408J

4

56

V1

5V

S1

Key = B

S2

Key = A

U2A

7404N

21

U2B

7404N

43 R1

1kohm

5V

VCC

U3A

7402N

2

31

X1

Determine the Boolean equationfor this circuit.

Ans: Boolean Equation after simplify: (A + B’) . (A’ + B)

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Combinational circuit

V2

5V

S1

Key = A

S2

Key = B

S3

Key = C

U1

AND2

R1

1kOhm

U3

OR2

U4

OR2

U5

AND2

U6

AND2

X1

U2

NOT

U7

NOT

U8

NOT

Construct digital logic circuit for Y=(A+BC’)((AB)’+C)

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Comparators

A comparator is a digital hardware electronic device that compares two numbers in binary form.

Output a 1 or a 0 at its output depending on whether they are the same or not.

Operation of a single bit comparator can be expressed as a truth table

Inputs Outputs

A B A < B A = B A > B

0 0 0 1 0

0 1 1 0 0

1 0 0 0 1

1 1 0 1 0

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http://en.wikipedia.org/wiki/Truth_table

KARNAUGH MAP

Karnaugh Map provide a systematic method for simplifying Boolean expressions.

Also called a K map.

What is Karnaugh map method?

A graphical method of simplifying logic equations or truth tables.

edited by: engr noor badariah

asan 85

1)Looping Groups of Two (Pairs)

Eg:


Looping K-MAP

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Looping K-MAP2)Looping Groups of Four (Quads)

Eg:

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Looping K-MAP3)Looping Groups of Eight (Octets)

Eg:

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MultiSim: Arithmetic Circuits, Flip-flops, Counters, Shift

Registers and Multiplexers

CHAPTER 2: DIGITAL ELECTRONICS WITH MULTISIM. edited by: engr noor badariah asan INTRODUCTION To...

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Transcript of CHAPTER 2: DIGITAL ELECTRONICS WITH MULTISIM. edited by: engr noor badariah asan INTRODUCTION To...