The Exclusive NOR Gate

The EXCLUSIVE NOR gate gives an output of 1 when both inputs are equal – both 0 or both 1. The symbol is shown below.

The truth table for the XNOR gate is shown below.

A

B

Output

0

0

1

1

0

0

0

1

0

1

1

1

The EXCLUSIVE NOR gate may be constructed from two NOT gates, two AND gates and an OR gate as shown below. The Boolean expresseion for the output is