Question

Design an XNOR gate with two inputs A and B using only NAND gates .Mention the expression in terms of A and B at the output of each NAND gate in your circuit diagram.

Answer 1

The XNOR gate can be designed using so-called NAND logic. The scheme is below:

The expression is

$$Q=(A\cdot B)+\big(\overline{A}\cdot\overline{B}\big).$$