For a 3-input NAND gate, if all inputs are high, the output is

For a 3-input NAND gate, if all inputs are high, the output is

• A. High
• B. Low
• C. Undefined
• D. Tri-state

Answer: (B)

A NAND gate outputs the opposite of the AND of all its inputs. For three inputs, that means the output is NOT(A AND B AND C). If all inputs are high (logic 1), then A AND B AND C is 1, and NOT(1) is 0, so the output is low. Any other input pattern will yield a high output because at least one input being low makes the AND result 0, and NOT(0) is 1. In a standard gate with valid inputs, you won’t see undefined or tri-state behavior here; the definite result when all inputs are high is a low output.

A NAND gate outputs the opposite of the AND of all its inputs. For three inputs, that means the output is NOT(A AND B AND C). If all inputs are high (logic 1), then A AND B AND C is 1, and NOT(1) is 0, so the output is low. Any other input pattern will yield a high output because at least one input being low makes the AND result 0, and NOT(0) is 1. In a standard gate with valid inputs, you won’t see undefined or tri-state behavior here; the definite result when all inputs are high is a low output.