## Logic gate:

- Block of hardware’s, on getting input they produce output 0 or 1.
- Input for logic gates are either 0 or 1.
- Output for logic gates are either 0 or 1.
- Each logic gate has its symbol.
- Operations of logic gate are represented by algebraic expressions.

## Names of logic gates:

- AND logic gate
- OR logic gate
- NOT logic gate
- XOR logic gate
- NAND logic gate
- NOR logic gate
- XNOR logic gate

## Logic gate operations:

Input variables : A, B Output variable : OP

- AND : OP = A.B
- OR : OP = A+B
- NOT : OP = A’
- XOR : Exclusive OR : OP = A’B+AB’ = A B
- NAND : NOT AND : OP = (AB)’
- NOR : NOT OR : OP = (A+B)’
- XNOR : Exclusive NOR : OP = A’B’+AB = (A B)’

## Logic gate symbols:

## Truth Table:

Table shows relationship between input and output variables in logic gates.