Which logic circuit outputs a 1 when at least one of its inputs is high (1)?

The OR gate is designed to output a high signal (1) when at least one of its inputs is high (1). This characteristic makes it an essential component in digital logic circuits where the goal is to activate an output when any one or more conditions are met. The function can be summarized with the truth table for the OR gate, which shows that the output is 1 for all input combinations except when both inputs are 0.

In contrast, the AND gate requires all inputs to be high for the output to be 1, thus it does not serve the same function as the OR gate. The NOR gate performs the opposite function of the OR gate, outputting a 1 only when all its inputs are low (0). The XOR gate outputs a 1 when the inputs are different, meaning it only produces a high output when one input is high and the other is low. This specificity makes each of these other logic circuits unsuitable when the requirement is simply to have a high output for any high input. Hence, the OR gate is the correct choice for the scenario presented.