Logic Gates #1

Logic Gates #1 - Logic Gates and Digital Circuits

Part 1: What is a Logic Gate?

What is a logic gate?

Transistors can be connected together to form Logic Gates. Think of these like lego pieces. When building a CPU, we put logic gates together like little blocks of lego to form a _____.

These logic gates (and the larger circuits) are used to control the flow of electricity that travels along the ___ from the ____

Most standard logic gates have two __________ and one ______________.

What is a truth table?

A chart of a circuit's inputs and outputs is called its _______.
The 'truth' part comes from ____ Logic where A ___________ indicates off/false. A _______ indicates on/true.
In order to help you predict the output of complex circuits, truth tables often have mid-values (see complex circuits later in the assignment) indicated by letters.

Part 2: And, Or & Not Logic Gates

And - If ALL inputs are on, the output is on. If even one input is off, the output is off.

Not - Reverses the input

Or - If ANY inputs are on, the output is on.

Note that is Computer Science 30, you learn about 3 more gates (Nand, Nor, Xor)

And Gate

A	B	X
0	0
0	1
1	0
1	1

Not Gate

B	X
0
1

Or Gate

A	B	X
0	0
0	1
1	0
1	1

Part 3: Combining Logic Gates into Complex Circuits

Circuit #1

A	B	Y	Z
0	0
0	1
1	0
1	1

Want to test a circuit? - https://logic.ly/demo/

Circuit #2

A	B	X	Y	Z
0	0
0	1
1	0
1	1

Circuit #3

A	B	C	D	X	Y	Z
0	0	0	0
0	0	0	1
0	0	1	0
0	0	1	1
0	1	0	0
0	1	0	1
etc.	That’s enough. You get the idea.	Do not continue this table past here.