An electronic logic gate whose output is logic 0 (false) only when any one of its inputs is logic 1 (true) and all the others are logic 0, otherwise the output is logic 1. It implements the logical operation of equivalence and has the same truth table. It is thus also known as an equivalence gate. Like the exclusive-OR gate it can be used as a simple digital comparator. The diagram shows the circuit symbol and truth table of a two-input gate.
Exclusive-NOR gate. Two-input EXNOR gate, circuit symbol and truth table