Question

A three-input NAND gate will have a HIGH output whenever ________?

Answer 1

A three-input NAND gate will have a HIGH output whenever one or more of its inputs are LOW, because a NAND gate provides the opposite output to an AND gate, and an AND gate only outputs HIGH when all inputs are HIGH.

Step-by-step explanation:

A three-input NAND gate will have a HIGH output whenever one or more of its inputs are LOW. A NAND gate is a digital logic gate that performs the opposite operation to that of an AND gate followed by a NOT gate. For an AND gate, the output is HIGH only when all of its inputs are HIGH. Therefore, for a NAND gate, when one or more inputs are LOW, the output becomes HIGH because the NOT operation inverts the LOW result of the AND operation.

To confirm this behavior, you can consider the truth table for a three-input NAND gate:

• If Inputs are 000, Output is HIGH
• If Inputs are 001, Output is HIGH
• If Inputs are 010, Output is HIGH
• If Inputs are 011, Output is HIGH
• If Inputs are 100, Output is HIGH
• If Inputs are 101, Output is HIGH
• If Inputs are 110, Output is HIGH
• If Inputs are 111, Output is LOW

The only time the output of a three-input NAND gate is LOW is when all three inputs are HIGH.