Q.Write the Boolean expression of XNOR gate.

The exclusive-OR (XOR) and exclusive-NOR (XNOR) gates are two special two-input logic gates that compare their inputs rather than simply combining them.

The XOR gate gives a HIGH output only when its two inputs are different — that is, when exactly one input is 1. Its Boolean equation is $Y = A \oplus B = \overline{A}B + A\overline{B}$, and its symbol is drawn like an OR gate with an extra curved line across the inputs. Because its output is 1 for an odd number of 1s, cascaded XOR gates form the basis of parity generators and checkers; for example $A \oplus B \oplus C$ is built from two two-input XOR gates. …