# What is Logic Gates

**LOGIC GATES:**

**The main Objectives is to understand the operation of logic gates.**

Logic Gates are used to build digital systems. The basic gates are AND, OR, NOT, NOR, NAND, EXOR and EXNOR gates. NAND and NOR gates are called universal gates as these gates can implement any Boolean function without any use of other gates. The basic operations of gates are explained below with truth table and gate symbol.

**AND GATE: **

The AND Gate is an electronic circuit which gives high output only when all of its inputs are high, in all other cases output is low. The logical equation for AND gate is

**Y=A.B** where Y is output and A and B are inputs.The dot (.) symbol is used to indicate AND operation.

Pin Configuration of AND gate

**OR GATE:**

The OR gate is an electronic circuit, that gives output high when any one or more inputs are high, in all other cases output is low. The logical equation for OR gate is **X= A+ B.**Where X is output and A and B are inputs.The plus (+) symbol is used to indicate OR operation.

Pin configuration of OR gate

**NOT GATE:**

The NOT gate is an electronic circuit, that produces output which is inverted version of input. It is also called as inverter. The logical equation for NOT gate is **X= ~X.**

Pin Configuration of NOT gate

**NAND GATE:**

The NAND gate is electronic circuit, that gives output low when all of its inputs are high, in all other cases output is high. The logical equation for NAND gate is **X= ~ (AB)**.

Pin configuration of NAND gate.

**NOR GATE:**

The NOR gate is electronic circuit, which gives output high when all of its inputs are low, in all other cases output is low. The logical equation for NOR gate is **Q= ~ (A+B). **Where Q is output and A and B are inputs.

Pin Configuration of NOR Gate

**XOR GATE:**

The XOR gate is electronic circuit, which gives output high only when any one of its input is high, in all other cases output is low. The logical equation for XOR gate is **X= A⊕B**. Where x is output and A and B are inputs.

The symbol is used to indicate XOR operation.

**XNOR GATE:**

The XNOR gate is electronic circuit, which gives output high only when all of its inputs are identical, in all other cases output is low. The logical equation for XNOR gate is** Y= ~(AxorB)**. Where Y is output and A and B are inputs.

Logical Symbol of XNOR Gate:

Pin Configuration of XNOR gate: