# INTRODUCTION OF LOGIC GATES

Binary logic deals with binary variables and with operations that assume a logical meaning.It is used to describe, in algebraic or tabular form, the manipulation of processing of binary information.The manipulation of binary information is done by logic circuits called gates. Gates are blocks of hardware that produce signals of binary 1 or 0 when input logic requirement are satisfied. A variety of logic gates are commonly used in digital computer system. Each gate has a distinct graphic symbol and its operation can be described by means of an algebraic expression. The input-output relationship of the binary variables for each gate can be represented in tabular form by a truth table. The basic logic gates are AND, Inclusive OR with multiple inputs and NOT with a single input. Each gate with more than one input is sensitive to either logic 0 or logic 1 input at any one of its input, generating the output according to its function.

## DEFINITION OF GATES

All operations within a computer are carried out by means of combinations of signals passing through standard blocks of built-in circuit that are known as logic gates. In other words, a logic gate is simply an electronic circuit which operates on one or more input singles.

### TYPES OF GATES

There are eight types of logic gates which can generate different outputs for the inputs. They can have any number of inputs lines but they have always a single output line. These eight logic gates as:

**AND Gate****OR Gate****NOT Gate or Invert Gate****NAND Gate****NOR Gate****Buffer Gate****XOR Gate or Exclusive-OR Gate****XNOR Gate or Exclusive-NOR gate**