Family Science Program Introduction to Electronics...2020/05/28 · Introduction for parents In...

© 2020 IBM Corporation

Family Science ProgramIntroduction to Electronics

Ruud Haring

05/26/2020 1


Introduction for parents In this class we will introduce basic electronic circuits and basic “Boolean logic” to explain how

computers do their magic – that is: what is going on inside.

The 1st part of the class includes two pencil-and-paper exercises. Parents: before the class, it is recommended to print at least page 54 and 55 at the very back of this handout. One copy of page 54 and multiple copies (e.g. 5x) of page 55 would be good.

The 2nd part of the class has an exercise that can be done on an external non-IBM website:https://logic.ly/demo. Please start this link before the 2nd class, so that you can use it right away.The web version allows you to load, but not save circuits.If you really like it, and want to save your creations, a desktop version is also available for free for a trial up to 30 days; then for sale.

Please feel free to ask questions and enjoy!

205/26/2020

https://logic.ly/demo


Have you ever wondered how computers work, inside?

You can do lots of things with computers:– do your homework– browse the internet– write a report– play video games– play music– even calculate …

So how does that all work ? How can some box of electronics do all that?

Let’s dive right in…

305/26/2020


Open up any electronics box and you will see something like this…

“printed circuit board”

with

“chips”

wires

other small stuff…

How is that made and how does it work?

405/26/2020

"© Raimond Spekking / CC BY-SA 4.0 (via Wikimedia Commons)"

https://creativecommons.org/licenses/by-sa/4.0/deed


It starts with sand and water …

505/26/2020

Sand is ground-up rock. It contains mostly silicon-dioxide (and some other stuff) extract the silicon

Water – we’ll talk about later…

https://www.slideshare.net/judan1970/unit-2-lesson-23-mixtures


https://www.sil-tronix-st.com/webuploads/display/200/Charlotte-Le-Mesle-Photographe-Sil-Tronix-ST-Transformation-Lingot-1.jpg

Silicon is melted and then “grown” into large cylinders (“ingots”) of very pure silicon

605/26/2020

https://media.wired.com/photos/5b68fc315bac5521a29ba720/master/w_1927,c_limit/silicon-96588401.jpg

On such a silicon slice (“wafer”) we then “print” our circuits.

When done (and tested), we saw the wafer into little squares: “chips”.

https://www.silicon.fr/wp-content/uploads/2011/12/Wafer-Silicon-Cr%C3%A9dit-photo-%C2%A9-Scanrail-Fotolia.com_.jpg

which are then sliced up…


A chip photograph (BlueGene/P)

705/26/2020

3 of these chips encapsulated in “modules”…

… and then assembledon a printed circuit board, with cooling fins on top, and other (memory) chipson the side13.16 x 13.16 mm die size

can be covered by a dime!


But why silicon ?

Silicon is shiny … like a metal it conducts electricity

But it is brittle … it breaks like glass but glass does not conductelectricity

805/26/2020


Silicon sits on the fence between metals and non-metals…

… means we can push it off the fence… one way or the other

We can make silicon conduct electricity … or we can make it non-conductive.Back and forth.

We can make silicon switch current on and off -- and do it very fast

And with switches, we can do a LOT…

905/26/2020


Water logic

1005/26/2020

A sink with a hot and cold water faucet

How can I get water to flow into the sink?

Water flows when we open valve A OR valve B(or both).

A B Water flows?0 0 00 1 11 0 11 1 1

Hot

A

Cold

B

?


Electrical circuits

1105/26/2020

XA light bulb with one switch

How can I get the light to go on?

Light goes on when we close the switch

Light bulb

Battery

switch


Same with electrical circuits

1205/26/2020

X

A B

A light bulb with two switches, A and B

Light goes on when we close switch A OR switch B(or both).

A B Light on ?0 0 00 1 11 0 11 1 1

Light bulb

Battery

switches



Water or electricity: the same OR logic applies

1305/26/2020

X

A B

A B Output0 0 00 1 11 0 11 1 1

Hot

A

Cold

B

?

A OR B

A

BO

logic gate -- OR gate


Examples of OR gates Home

Car

1405/26/2020

X

A B C D


More water logic

1505/26/2020

A

B

?

Now I have two water valves (in series).

How can I get water to flow into the sink?

Water flows when we open valve A AND valve B

A B Water flows?0 0 00 1 01 0 01 1 1


Same with electrical circuits

1605/26/2020

X

A

B

A light bulb with two switches in series


Light goes on when we close switch A AND switch B

A B Light on ?0 0 00 1 01 0 01 1 1


Water or electricity: the same AND logic applies

1705/26/2020

A B Output 0 0 00 1 01 0 01 1 1

A AND B

AB

?

X

A

B

A

BO

AND gate


Examples of AND circuits Home

Car

1805/26/2020


Inverter (NOT gate)

1905/26/2020

A Output 0 11 0

NOT A

A O

Output is 1 if input is 0Output is 0 if input is 1

NOT gate -- inverter


Interesting facts This manipulation of 0s and 1s with AND, OR and NOT is called “Boolean logic”,

after British mathematician George Boole (1815-1864).He lived long before electronics existed! I don’t know if he even had running water with faucets and sinks…

With AND, OR and NOT gates, you can actually make any logical circuit,meaning any circuit that handles 1’s and 0’s.

You don’t really need anything else!

But … there are other circuits that are handy to have around as building blocks.

– These can be built from AND/OR/NOT, but we tend to think of them as building blocks by themselves.

One such (slightly more complicated) building block is the following.

2005/26/2020


Interesting combination: XOR (exclusive OR)

2105/26/2020

(A and (not B)) or (B and (not A))


Light goes on when A and B are different

A B Light on ?0 0 00 1 11 0 11 1 0

X

A B

not_B not_A

AB O

A XOR B

XOR gate


Exercise

2205/26/2020

A B Output0 0 0

0 1 1

1 0 1

1 1 1

A OR B

A=0

?

?

?

?

B=0

01

11

10

A B Output0 0 0

0 1 0

1 0 0

1 1 1

A AND B

0

?

?

?

?

1

11

10

00

A B Output0 0 0

0 1 1

1 0 1

1 1 0

A XOR B

1

?

?

?

?

0

00

01

11

1

0

1

1

0

1

0

0

1

1

0

0


Combinations A single “0” or “1” is called a “bit”.

– Note: Bits are the smallest units of information.Computer scientists and engineers use bits (0 or 1) to represent things that have only 2 possibilities: a switch that can be open or closed, a light that can be “off” or “on”, a statement that can be “false” or “true”, an answer that can be “no” or “yes” a voltage that can be “low” or “high”.

But what have these “bits” have to do with anything real?

With combinations of bits, you can represent lots of things:– Colors– Text– Numbers– Sound

… which means that with electronic circuits you can handle that information:videos, games, reading, writing, calculating, playing/making music, …

2305/26/2020


Colors

2405/26/2020

Any little dot (called “pixel”) on your screenis actually 3 dots: a red, a green and a blue dot.

You may be able to see that with a magnifying glass.

The bits tell the screen which colored dots to switch on or off. Your eye then mixes the colors so that you end up seeing the colors in the table.

With more bits, you can do more tricks: like turn green off – little green – much green – full green.Then you get different color hues.

Note: Modern screens have e.g. 24 bit color, meaning 8 bits each for blue, green and red.This allows 256 shades of each color, or 256*256*256 = 16.7 million colors altogether.


Characters

2505/26/2020

Any letter you type on the keyboardbecomes a little series of eight high and low voltages, expressed as 1’s and 0’s -- thus 8 “bits”.

These fly from your keyboard to the computer,go on the hard drive, fly over the internet.

Only when they get back to your screen or printerdo you see a familiar letter again!

Such a group of 8 bits is called a “byte”.

Note: You will have heard of kiloBytes (1000 characters, say like an e-mail)MegaBytes (a million characters, like a book)GigaBytes (a DVD holds a couple of GB)


NumbersBinary Decimal

000 0001 1010 2011 3100 4101 5110 6111 7

2605/26/2020

Humans think in the familiar decimal numbers…but computers only handle “binary numbers”.

With 3 bits that each can be 0 or 1 (thus, 2 possibilities) you can make 2*2*2=8 possible combinations.

With those 8 “binary” combinations you can express our decimal numbers 0 to 7.

How do you represent a bigger number, like 8?


NumbersBinary Decimal

0000 0

0001 1

0010 2

0011 3

0100 4

0101 5

0110 6

0111 7

1000 8

1001 9

1010 10

1011 11

1100 12

1101 13

1110 14

1111 152705/26/2020

With 4 bits you can make 2*2*2*2 = 16 combinations,enough to express decimal numbers 0 to 15.

So: add one bit (in front), and you get twice as many combos.

How would you make 16?

Note: Computers encode whole numbers (integers) into strings of 32 or 64 bits -- so that they can handle really large numbers.

How big? 64 bits max = (2**64 – 1) ~ 18 billion-billion (18 with 18 zeroes)Suggestion: Look up the grains-of-rice story!


Adder So can we do computing with these binary numbers?

YES!– We said before that once something is represented as zeroes and ones (bits),

our AND/OR/NOT gates are all you need to manipulate these bits.

– So…with the right combination of gates we can manipulate binary numbers to do such things as addition (and subtraction), multiplication, division.

– The trick is to have the right gates, and wire them together correctly in a larger circuit that does what you want it to do.

So next we will look at an “adder” circuit - specifically a “3-bit adder”: a circuit that can do any addition (from 0+0 up to 7+7) using binary numbers

2805/26/2020


Adder exercise

2905/26/2020

A2 A1 A0B2 B1 B0

Decimal

000 0

001 1

010 2

011 3

100 4

101 5

110 6

111 7

Inputs

S3 S2 S1 S0 Decimal

0000 0

0001 1

0010 2

0011 3

0100 4

0101 5

0110 6

0111 7

1000 8

1001 9

1010 10

1011 11

1100 12

1101 13

1110 14

1111 15

Output

Pick any two numbers from above table to add up.

Example: 3+6Inputs:3 A2, A1, A0 = 0116 B2, B1, B0 = 110

Output:S3, S2, S1, S0 = 1001 9

https://researcher.watson.ibm.com/researcher/files/us-wendych/IntroElectro_adder.pdf

0 1 11 1 0

00110 1

00

1

01

S31



Bigger adder

3005/26/2020

S3S3S4

A3B3

G3 P3

C2

S4S5

A4B4

G4 P4

C3

S5S6

A5B5

G4 P4

C3

6 bits inputs, 7 bits output can do any addition up to 63 + 63 = 126“Ripple-carry adder”


Speed So addition with bits works … but looks a little cumbersome.

However, the AND, OR, XOR gates are made out of silicon and therefore can do it very fast. And they can do it all day!

How fast: if I drum my fingers, I can do 12 taps/second -- which is about 1 million per day.– A billion taps would take me 1000 days – almost 3 years!

– Any modern computer, however, like your laptop, can do a billion additions in a second! Note: It actually has to do 100s-of-millions of additions per second just to change the

screen when playing a video or videogame!

Here at IBM we have designed “supercomputers” that are thousands to even millions of times faster than that – used for really big calculations like weather/climate simulations, or for calculating what drugs might help with diseases, like COVID-19.The chips shown before are part of such a supercomputer – see next page.

3105/26/2020

© 2020 IBM Corporation 32

IBM’s BlueGene/P was one of the fastest computers in the world 2008-2012.Was preceded by BlueGene/L (2004-2008) and succeeded by BlueGene/Q (2012-2020) and Summit/Sierra (2018 – current).

05/26/2020


So that’s the story Anything electronic has at its heart silicon chips

These chips contain millions of tiny circuits (logic gates), that are actually quite simple: AND, OR, XOR, NOT

Collections of these circuits, wired together, pass each 0’s and 1’s to each other, and can do something interesting together: like addition or multiplication … or playing music, or displaying information on a screen, or communicate information between each other.

… and do it all very fast -- because silicon can switch electrical currents on/off very fast.

Since text, numbers, colors and sound can all be expressed in 0’s and 1’s, that means that computers can handle all of that, using these simple logic gates…

The result is that you can see this remote presentation, you can hear my voice, you can do your homework, browse the internet, play music, etc.

So that’s how computers work on the inside! 3305/26/2020

Hands-on circuitsThis will be in the second part of the class

3405/26/2020


Hands-on circuits In the class we have “suitcases” to wire circuits together

From home, we can do it on the web: e.g. https://logic.ly/demo

3505/26/2020

https://logic.ly/demo

© 2020 IBM Corporation 3605/26/2020

1. Inverter(NOT gate)

2. OR gate

3. AND gate

4. XOR gate

A Out

0 1

1 0

A B Out0 0 0

0 1 1

1 0 1

1 1 1

A B Out0 0 0

0 1 0

1 0 0

1 1 1

A B Out0 0 0

0 1 1

1 0 1

1 1 0


Note: the circuits on this page and next work well with our electronic suitcases, because each gate has a built-in delay,and because undriven inputs are “pulled down” (i.e. are 0).

On logic.ly a few settings will need to be invoked to make it work similarly:• Edit -> Document Settings -> No connection: Low• Edit -> Application Settings -> Simulation -> Limit Propagation to Frame Rate• Note buttons at lower left: Reset, Start/Pause Simulation, Advance Simulation One Step

10 Out

5. Delay Line

Tips: • Attach a light bulb to each output. Note the alternating pattern!• “One step” the simulation : ►► button at bottom left.• What happens if you use a clock instead of a switch at the input?

NOR gate = NOT OR = OR followed by inverter (NOT gate)

Not connected or drive by fixed 0


OFF 1ON 0 Out

6. Ring Oscillator

Same as previous circuit, but we added the blue “feedback” wire.

Tips: • Attach a light bulb to each output• Use the reset ▐◄, start/pause ► / ▐ ▌ and one-step ►► buttons at bottom left

Question:• It works with 5 gates. Would it work with 4? With 3? With 2? With 1? Try it!!

How would you explain what you see?


A1B1

A0B0

decimal

0 0 0

0 1 1

1 0 2

1 1 3

Inputs

S2 S1 S0 decimal

0 0 0 0

0 0 1 1

0 1 0 2

0 1 1 3

1 0 0 4

1 0 1 5

1 1 0 6

1 1 1 7

Output

Demonstration circuits in logic.ly

4005/26/2020


1. Inverter (NOT gate)

• Input is toggle switch. You can toggle it between 0 = up and 1 = down.• Note that both the input and the output have a lightbulb and a 0/1 “digit” indicator, to make it easy to see the 0 and 1.• Does it behave like the truth table?• You can delete the toggle switch and replace it with the clock symbol as a driver.

(But if you delete something, you also lose its connecting wires, so you’d have to rewire it.)

A Out

0 1

1 0

05/26/2020 41


2. OR gate

The two toggle switches are the two inputs, A and B

Again, each input and output has a light bulb and a 0/1 indicator

Can you toggle the inputs and verify that this indeed behaves like the truth table?4205/26/2020

A B Out0 0 0

0 1 1

1 0 1

1 1 1


3. AND gate




A B Out0 0 0

0 1 0

1 0 0

1 1 1


4. XOR gate




A B Out0 0 0

0 1 1

1 0 1

1 1 0


5. Delay Line

There is one toggle switch -- which you may want to replace with a clock.

Again, each input and output has a light bulb and a 0/1 indicator.

All intermediate stages have a light bulb.

Can you see how the signal propagates left-to-right?

Bottom left buttons allow you to “pause” and “single step” the simulation

4505/26/2020

On logic.ly a few settings will need to be invoked to make it work:• Edit -> Document Settings -> No connection: Low• Edit -> Application Settings -> Simulation -> Limit

Propagation to Frame Rate• Note buttons at lower left: Reset, Start/Pause

Simulation, Advance Simulation One Step


6. Ring Oscillator

Same circuit as delay line – but with a wire that feeds output back to the first NOR gate.

There is one toggle switch -- it now serves to start/stop the circuit

Again, each input and output has a light bulb and a 0/1 indicator.

It may require little playing to make it work.Start with Pause simulation, switch down (1 = circuit off), reset. Single step a few times, until it is stable. Then switch ON (up), single step further. Then let it run!

4605/26/2020


7. 2-bit adder

The A inputs have the “ones” switch A0 above the “two-s” switch A1 By switching A0 and A1, you can make numbers 0 (up-up), 1 (down-up), 2 (up-down), 3 (down-down), as indicated by the top digit.

Same for the B0 and B1 -- indicated by bottom digit.

The sum is gathered in the right hand side digit indicator

Together, this circuit will add any number up to 3+3=6

Table on the right spells out all the16 possible additions you can do with this circuit, and all the binary stuff.

For bigger numbers, see page 29, which repeats the bottom 5 gates (a “full adder”) once more.On p.30 we show extension to a 6-bit adder.

4705/26/2020


Questions ? Family Science Introduction to Electronics team:

– Ruud Haring– George Almasi– Eduardo Castro– Paul Crumley

Family Science coordinator:– Grace Kaplan

4805/26/2020

Extras

4905/26/2020


Silicon is magical stuff -- it is a “metalloid”,sitting on the fence between metals and non-metals

5005/26/2020

https://commons.wikimedia.org/wiki/File:Simple_Periodic_Table_Chart-en.svg

MetalsNon-metals

Periodic system of the elements


Binary NumbersBinary Decimal

0000 0

0001 1

0010 2

0011 3

0100 4

0101 5

0110 6

0111 7

1000 8

1001 9

1010 10

1011 11

1100 12

1101 13

1110 14

1111 155105/26/2020

In the familiar decimal system, the position of each digit matters.

For example, 4537 means (working right-to-left): 7 in the “ones” position (100) 73 in the “tens” position (101) 305 in the “hundreds” position (102) 5004 in the “thousands” position (103) 4000 +

4537

The binary number system also works this way, but with the positions taken by powers of 2 instead of powers of 10.For example, binary 1101 means (again, working right-to-left):

1 in the “ones” position (20) 10 in the “twos” position (21) 01 in the “fours” position (22) 41 in the “eights” position (23) 8 +

13

Q: what decimal number corresponds to 0010 1010 ?what decimal number corresponds to 1101 1011 ?


Number systems -- it’s all about which tribe you belong toRoman Decimal Binary Hexa-

decimalN 0 0000 0

I 1 0001 1

II 2 0010 2

III 3 0011 3

IV 4 0100 4

V 5 0101 5

VI 6 0110 6

VII 7 0111 7

VIII 8 1000 8

IX 9 1001 9

X 10 1010 A

XI 11 1011 B

XII 12 1100 C

XIII 13 1101 D

XIV 14 1110 E

XV 15 1111 F5205/26/2020

Roman numerals worked, were used in Europe up to the 1300s, and are still found on clock faces and buildings. But calculations must have been very cumbersome. Good that you don’t need to go to a roman or medieval school!

Most humans these days use the (Hindu-Arabic) Decimalsystem. But different languages use different symbols!

Electronics (computers, robots, …) use binary numbers, because that simply corresponds to voltage on / voltage off.

Computer scientists and engineers use hexadecimalas shorthand for groups of 4 bits. It is simply more convenient to work with C0FFEE37 than with 1010 0000 1111 1111 1110 1110 0011 0111

Print-outsBefore the class, please print one copy of slide 54and 5 copies (or more) of slide 55

5305/26/2020


Exercise

5405/26/2020

A B Output0 0 0

0 1 1

1 0 1

1 1 1

A OR B

A=0

?

?

?

?

B=0

01

11

10

A B Output0 0 0

0 1 0

1 0 0

1 1 1

A AND B

0

?

?

?

?

1

11

10

00

A B Output0 0 0

0 1 1

1 0 1

1 1 0

A XOR B

1

?

?

?

?

0

00

01

11


Adder exercise

5505/26/2020

A2 A1 A0B2 B1 B0

Decimal

000 0

001 1

010 2

011 3

100 4

101 5

110 6

111 7

Inputs

S3 S2 S1 S0 Decimal

0000 0

0001 1

0010 2

0011 3

0100 4

0101 5

0110 6

0111 7

1000 8

1001 9

1010 10

1011 11

1100 12

1101 13

1110 14

1111 15

Output

Example: 3+6=9Inputs:3 A2, A1, A0 = 0116 B2, B1, B0 = 110

Output:S3, S2, S1, S0 = 1001 9https://researcher.watson.ibm.com/researcher/files/us-wendych/IntroElectro_adder.pdf

S3


Family Science Program Introduction to Electronics...2020/05/28 · Introduction for parents In...

Documents

Transcript of Family Science Program Introduction to Electronics...2020/05/28 · Introduction for parents In...