# AND Gate | Truth Table and Circuit Diagram

By Priyanshu Vaish|Updated : June 3rd, 2022

A logic gate is a physical device that performs a logical operation in one or more logical fain-in or inputs and produces a logical output. This article helps us to understand the logical AND gate. The output of a "AND Gate" only returns "HIGH" when all the inputs are "HIGH".

The AND gate is one of the basic or fundamental logic gates of the digital system. The And gate if we want to use then the IC7408 is used in which there are four independent gates, each of which performs the logical AND operation.

## What is AND Gate?

The AND gate will have two or more fan-in or inputs but only one output. The function of a logical AND gate effectively finds the minimum between two binary digits. The logic symbol two-input AND gate is:

The output of the two or more fan-in or input is said to be 'true' or '1' when all the fa-in or inputs that are connected is 'true' or '1'. Otherwise, if any fan-in or input is '0', the output becomes zero.

## AND Gate Truth Table

The AND gate truth table is for the two fan-in or inputs that are A and B. It has only one output as Y. The output is logic '0' if any inputs A and B are LOW (logic '0'). However, the output is 1 only when all the inputs are 1. The AND gate truth table is as follows:

The logical expression from the above AND gate truth table is Y= AB.

## Properties of AND Gate

The AND gate follows commutative property. That is if we have two inputs, A and B, then AB = BA. Let us suppose the input A is '1' and B is '0', so the output Y is '0' as per the given AND gate truth table. The same output we get in the commutative property as:

AB = 1.0 = 0

BA = 0.1 = 0

The AND gate also follows associative property. That is if we have three inputs, A, B and C, then (AB)C= A(BC). Let us suppose the input A is '1', B is '0', and C is '0', so the output Y is '0' as per the AND gate truth table. The same output we get in the commutative property as:

(AB)C =(1.0).0 = 0.0 = 0

A(BC) =1.(0.0) = 1.0 = 0

For AND operations, we have enabled and disabled inputs that are as follows:

If control = 0;

No change in the output. Hence logic '0' is considered as disabled input for AND gate.
If control = 1;

Due to change in the input-output also changes; therefore logic '1' is enable input for AND gate.

## Circuit Diagram of AND Gate

Based on the above AND gate truth table, the switching circuit diagram of AND gate is shown below. We have two inputs or switches, A and B, connected serially, and one blub is also connected serially with two inputs the circuit diagram of AND gate is as follows:

The bulb will glow only when both switches A and B are closed or at logic '1'. If any of the switches A and B are open or logic '0', then the bulb will not glow.

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## FAQs on AND Gate

• The AND gate truth table used to express the Boolean expression of a logic gate function is commonly known as the truth table. The AND gate truth table shows the possible input combination to the gate or circuit with the output depending upon the combination of these fain-in or input(s).

• The main difference between the AND gate and OR gate is that the AND gate performs the multiplication of the logical input. In contrast, the OR logic gate performs the addition of the logical inputs.

• As the name suggests that the 3 inputs mean the AND gate has three inputs or fain-in and have only one output. If all the three inputs are high, then the output is high. Otherwise, if any of the three inputs is low, the output is low.

• The AND gate is named as AND because suppose if the true means' 1' and false means' 0', then the logic gate acts as the "and" operator. The logical expression of the AND gate is Y= AB, where A and B are input to the AND gate.

• The logic gates are the fundamental building blocks of any digital system. The logic gates are classified into three different categories that are as follows:

Basic gates

Universal gates

Special gates

The basic logic gates are NOT, OR, AND gates.