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Basic Logic Gates / and gate , or gate and many more gate

 

Basic Logic Gates

Logic gates are an important concept if you are studying electronics. These are important digital devices that are mainly based on the Boolean function. Logic gates are used to carry out logical operations on single or multiple binary inputs and give one binary output. In simple terms, logic gates are the electronic circuits in a digital system.

In this lesson, we will further look at the different types of basic logic gates with their truth table and understand what each one is designed for.

Table of Content

Types of Basic Logic Gates

There are several basic logic gates used in performing operations in digital systems. The common ones are;

  • OR Gate
  • AND Gate
  • NOT Gate
  • XOR Gate

Additionally, these gates can also be found in a combination of one or two. Therefore we get other gates such as NAND Gate, NOR Gate, EXOR Gate, EXNOR Gate.

Also Read: Transistor

OR Gate

In OR gate the output of an OR gate attains the state 1 if one or more inputs attain the state 1.

Logic symbol of OR gate

 

The Boolean expression of OR gate is Y = A + B, read as Y equals A ‘OR’ B.

The truth table of a two-input OR basic gate is given as;

ABY
000
011
101
111

AND Gate

In AND gate the output of an AND gate attains the state 1 if and only if all the inputs are in state 1.

Logic Symbol of AND Gate

 

The Boolean expression of AND gate is Y = A.B

The truth table of a two-input AND basic gate is given as;

ABY
000
010
100
111

NOT Gate

In NOT gate the output of a NOT gate attains the state 1 if and only if the input does not attain the state 1.

Logic Symbol of NOT gate

 

 

The Boolean expression is Y =

, read as Y equals NOT A.

The truth table of NOT gate is as follows;

AY
01
10

The three gates (OR, AND and NOT), when connected in various combinations, give us basic logic gates such as NAND, NOR gates, which are the universal building blocks of digital circuits.

NAND Gate

This basic logic gate is the combination of AND and NOT gate.

Logic Symbol of NAND gate

 

The Boolean expression of NAND gate is Y =

The truth table of a NAND gate is given as;

ABY
001
011
101
110

NOR Gate

This gate is the combination of OR and NOT gate.

Logic Symbol of NOR

 

 

The Boolean expression of NOR gate is Y =

The truth table of a NOR gate is as follows;

ABY
001
010
100
110

Exclusive-OR gate (XOR Gate)

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