An XNOR (exclusive NOR) gate is a fundamental element in the field of digital electronics and computer engineering. It's a basic logic gate that outputs true or '1' only when the number of true inputs is even. In simpler terms, an XNOR gate will output true if the inputs are the same, either both '0' or both '1', making it also known as the 'equivalence gate'.
This gate can be synthesized by combining other basic gates such as AND, OR, and NOT gates. Alternatively, it can also be regarded as an XOR gate with a NOT gate connected to its output, effectively inverting the output of the XOR gate.
The XNOR gate is represented by a particular symbol in digital circuit diagrams, and its behavior is summarized in a truth table. For a two-input XNOR gate, if both inputs are '0' or both are '1', the output is '1'. If the inputs are dissimilar, the output is '0'. This behavior can be expressed algebraically with Boolean expressions.
Applications of the XNOR gate span various domains of digital systems, including but not limited to binary adders, parity generators and checkers, and in the creation of certain types of encoders and decoders. Understanding the operation of an XNOR gate is essential to grasp the functionality of complex digital logic circuits.