Which logic gate will provide an active high output only when all inputs are different?

Which logic gate will provide an active high output only when all inputs are different?

• A. AND
• B. OR
• C. NAND
• D. XOR

Answer: (D)

XOR, or exclusive OR, is high only when the inputs are not the same. With two inputs, that means one is 1 and the other is 0, so the output goes active. If both inputs are 0 or both are 1, the output stays low. This matches the idea of producing an active high only when all inputs are different for the common two-input case. For more than two inputs, XOR is high when an odd number of inputs are high, which still reflects a selective, non-equal condition rather than simply all inputs being different. Other gates don’t fit: AND requires every input to be high, OR requires at least one input to be high, and NAND is the inverse of AND.

XOR, or exclusive OR, is high only when the inputs are not the same. With two inputs, that means one is 1 and the other is 0, so the output goes active. If both inputs are 0 or both are 1, the output stays low. This matches the idea of producing an active high only when all inputs are different for the common two-input case. For more than two inputs, XOR is high when an odd number of inputs are high, which still reflects a selective, non-equal condition rather than simply all inputs being different. Other gates don’t fit: AND requires every input to be high, OR requires at least one input to be high, and NAND is the inverse of AND.