In a 3-input AND gate, how many inputs must be high for a high output?

In a 3-input AND gate, all three inputs must be high for the output to also be high. This logical operation is based on the definition of an AND gate, which produces a high output (logic 1) only when all its inputs are high. In this case, with three inputs, the only configuration that results in a high output is when each of those three inputs is receiving a high signal.

This specification distinguishes it from other types of gates, such as OR gates or NAND gates, where the required combination of inputs for a high output varies. The critical characteristic of the AND gate reinforces the necessity for all inputs to meet the high signal criterion simultaneously to achieve the desired output. Thus, for a high output from a 3-input AND gate, three inputs must indeed be high.