Which gate is the opposite of AND?

Which gate is the opposite of AND?

• A. NOR gate
• B. XOR gate
• C. NAND gate
• D. OR gate

Answer: (C)

Opposite here means the inverse of the AND result. An AND gate gives true only when both inputs are true. The gate that flips that result every time is the NAND gate, since it outputs NOT(A AND B). In other words, NAND is true for all input combinations except when both inputs are true. For two inputs, that means NAND is false only when both are true, and true in the other three cases, exactly the inverse of AND. The other gates don’t match this inversion: NOR inverts OR, XOR is true when inputs differ, and OR is true if either input is true. So the NAND gate best fits as the opposite of AND.

Opposite here means the inverse of the AND result. An AND gate gives true only when both inputs are true. The gate that flips that result every time is the NAND gate, since it outputs NOT(A AND B). In other words, NAND is true for all input combinations except when both inputs are true. For two inputs, that means NAND is false only when both are true, and true in the other three cases, exactly the inverse of AND. The other gates don’t match this inversion: NOR inverts OR, XOR is true when inputs differ, and OR is true if either input is true. So the NAND gate best fits as the opposite of AND.