Fundamental Logic Gates

And, Or, Not

Logic Gates: The Basics

Regulate the flow of electricity within circuits to perform desired functionalities

Each gate receives one or more inputs but has only one output

Represented using Schematics, Words, Symbols, and Boolean Equations

Logic Gates and Transistors

Logic Gates: ANDSchematic Symbol Boolean Equation

• Y = A • B

(Output) Y is True:Only if both (Inputs) A and B are true.

Aside Boolean Variables

Boolean variables are always capital letters and can only take on the values T (true) or F (false).

For Example:A=True B=False X=true…

Logic Gates: AND continued… Ex. Are the following statements true or false ?

My name is Mr.Kurz and this is Room 231. I am a human and I am the Prime Minister of Canada.

A B Y0 0 00 1 01 0 01 1 1

A B YF F FF T FT F FT T T

Truth Tables:

or

Note on Truth Tables

There is only one pattern to follow!A B YF F FF T FT F FT T T

A B Y0 0 00 1 01 0 01 1 1

ANY other way is wrong!

Logic Gates: ORSchematic Symbol Boolean Equation

+ Y = A + B

(Output) Y is True:Only if (Inputs) A, B, or both A and B are true.

Logic Gates: OR continued… Ex. Are the following statements true or false ?

This class is ICE4M or is in Room 503. I am a human or I am the Prime Minister of Canada.

A B Y0 0 00 1 11 0 11 1 1

A B YF F FF T TT F TT T T

Truth Tables:

or

Logic Gates: NOTSchematic Symbol Boolean Equation

¯ Y = A

Output (Y) is True:Only if Input (A) is false.

Logic Gates: NOT continued… Ex. Which of these are true or false?

This class is not ICE4M. I am not the Prime Minister of Canada.

A Y0 11 0

A YF TT F

Truth Tables:

or

Example: Create a truth table for the following circuit:

Steps: Create Table Fill in A, B, C Solve one gate at a

time using in betweencolumns on the table

Solve for Y

A B C A • B (A+B)•C0 0 00 0 10 1 00 1 11 0 01 0 11 1 01 1 1

00000011

01010111

Additional Info

Equivalent Terminology:

For ‘n’ inputs into any logic gate, there will be 2n rows in your truth table.

True 1 on open High VFalse 0 off closed Low V

The other three gates

NOR – “Not Or” NAND – “Not And” Xor - “One or the other, not both”

Today

1. Complete the Logic Gate Summary Chart2. Use the IC schematics on the resources

page to set up and test each of the 6 logic gates.

Pin 14 goes to Power Pin 7 to ground.