Which logical gate's truth table yields Y = 0 only when both inputs A and B are 1?

Which logical gate's truth table yields Y = 0 only when both inputs A and B are 1?

• A. AND
• B. OR
• C. NAND
• D. NOR

Answer: (C)

Understanding how a gate maps input combinations to an output using its truth table. A NAND gate is the negation of an AND gate, so its output is the opposite of A AND B. When both inputs are 1, A AND B is 1, and the NAND output becomes 0. In all other input combinations, A AND B is 0, so the NAND output is 1. That means the output Y is 0 only when both inputs are 1, which fits the requirement. The AND gate would yield 0 whenever any input is 0, not only when both are 1. The OR gate would yield 0 only when both inputs are 0. The NOR gate would yield 0 whenever at least one input is 1, including the cases where only one input is 1, not just when both are 1.

Understanding how a gate maps input combinations to an output using its truth table. A NAND gate is the negation of an AND gate, so its output is the opposite of A AND B. When both inputs are 1, A AND B is 1, and the NAND output becomes 0. In all other input combinations, A AND B is 0, so the NAND output is 1. That means the output Y is 0 only when both inputs are 1, which fits the requirement. The AND gate would yield 0 whenever any input is 0, not only when both are 1. The OR gate would yield 0 only when both inputs are 0. The NOR gate would yield 0 whenever at least one input is 1, including the cases where only one input is 1, not just when both are 1.