## BASIC DIGITAL: LOGIC GATES AND DETAILS

Digital is a part of Electronics. Basically electronics has two different types, one is Analog and the other one is Digital. Analog circuits are mainly deals with the analogues signal, means it mainly consists mechanical circuits. On the other hand Digital circuits are deals with the digital signals, means it consists of digital display.

 Analog Clock

 Digital Clock

Here we will discuss about the basic digital circuits or rather the basic blocks of the digital circuits.
To know brief about digital circuits’ at-first one should know about Logic Gates.

Logic gates are the basic building blocks of any Digital Circuit. These are called ‘Gates’ as we can give inputs and the gate gives us an output and these gates work logically.

Basically there are 7 logic gates; AND, OR, NOT, NAND, NOR, XOR & XNOR. The symbol of each gate, their expressions and the Truth tables are given below :

## AND Gate:

Symbol:
Inputs: A & B  Output: Y

Expression: Y = A.B

Truth Table:
 A B Y 0 0 0 0 1 0 1 0 0 1 1 1

## OR Gate:

Symbol:
Inputs: A & B    Output: Y

Expression: Y = A+B

Truth Table:
 A B Y 0 0 0 0 1 1 1 0 1 1 1 1

## NOT Gate:

Symbol:
Inputs: A & B   Output: Y

Expression: Y = A

Truth Table:
 A Y 0 1 1 0

## NAND Gate:  AND+NOT

Symbol:
Inputs: A & B  Output: Z

Expression: Z = A.B

Truth Table:
 A B Z 0 0 1 0 1 1 1 0 1 1 1 0

## NOR Gate:  OR+NOT

Symbol:
Inputs: A & B   Output: Z

Expression: Z =  A+B

Truth Table:
 A B Z 0 0 1 0 1 0 1 0 0 1 1 0

## XOR Gate:

Symbol:
Inputs: A & B   Output: Y

Expression: Y = A B + AB

Truth Table:
 A B Y 0 0 0 0 1 1 1 0 1 1 1 0

## XNOR Gate: XOR+NOT

Symbol:
Inputs: A & B   Output: Y

Expression: Y = AB +  A . B

Truth Table:
 A B Y 0 0 1 0 1 0 1 0 0 1 1 1

### A Final Result of all Truth Tables of the Gates :

 A B AND OR NAND NOR XOR XNOR 0 0 0 0 1 1 0 1 0 1 0 1 1 0 1 0 1 0 0 1 1 0 1 0 1 1 1 1 0 0 0 1