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.