Which gate outputs true when both inputs are false?

The NAND gate operates in such a way that it outputs a true value (1) unless both of its inputs are true (1). In the specific scenario where both inputs are false (0), the NAND gate will output true (1). This characteristic of the NAND gate makes it unique when compared to other gates.

For clarity, an AND gate would require both inputs to be true (1) to output true (1). Similarly, an OR gate needs at least one of its inputs to be true (1) to yield a true output. The XOR gate outputs true (1) only when the inputs differ; thus, if both inputs are false, it would also output false (0). Therefore, only the NAND gate fulfills the condition of outputting true when both inputs are false.