Which logic gate has the output ‘1’ only when both inputs are the same ?

The XNOR gate, also known as the Exclusive-NOR or equivalence gate, produces a high output ('1') only when both inputs are identical. This means if the inputs are (0, 0) or (1, 1), the output is '1'; otherwise, it is '0'. In contrast, an AND gate outputs '1' only when both inputs are '1', failing the (0, 0) case. An OR gate outputs '1' if at least one input is '1', which includes (0, 1) and (1, 0), making it incorrect. The XOR gate outputs '1' only when inputs are different (0, 1 or 1, 0), which is the exact opposite of what is required. Therefore, only the XNOR gate satisfies the condition where the output is '1' exclusively when both inputs match.