Question

Explain the fundamental gates with an expression and truth table.

Answer 1

A gate is a basic electronic circuit that operates on one or more signals to produce an output signal.
The three fundamental gates are AND, OR, and NOT gates.

AND Gate: 

The AND gate can have two or more input signals and produce an output signal. The output is “true” only when both inputs are “true”, otherwise, the output is “false”. In other words, the output will be 1 if and only if both inputs are 1; otherwise, the output is 0. The output of the AND gate is represented by a variable say C, where A and B are two and if input boolean variables. In boolean algebra, a variable can take either of the values ‘0’ or ‘1’. The logical symbol of the AND gate is

The truth table for AND gate is

Input		Output
A	B	C
0	0	0
0	1	0
1	0	0
1	1	1

OR Gate: 

The OR gate gets its name from its behavior like the logical inclusive “OR”. The output is “true” if either or both of the inputs are “true”. If both inputs are “false” then the output is “false”. In other words, the output will be 1 if and only if one or both inputs are 1; otherwise, the output is 0. The logical symbol of the OR gate is

The truth table for OR gate is

Input		Output
A	B	C
0	0	0
0	1	1
1	0	1
1	1	1

NOT Gate: 

The NOT gate, called a logical inverter, has only one input. It reverses the logical state. In other words, output C is always the complement of the input. The logical symbol of the NOT gate is

The truth table for NOT gate is

Input	Output
A	C
1	0
0	1