What do you call the device that limits current and provides protection in a circuit?

The device that limits current and provides protection in a circuit is a fuse. Fuses are designed to protect electrical circuits by breaking the circuit when the current exceeds a certain threshold. This prevents excessive current flow that can lead to overheating and potential damage to components or even electrical fires. When a fuse blows, it effectively disconnects the circuit, ensuring that the current does not continue to flow and cause harm.

In contrast, a resistor primarily limits the current flow in a circuit but does not provide protection against overcurrent situations. It operates continuously under normal conditions and does not disconnect the circuit when a fault occurs. A capacitor stores electrical energy temporarily and does not function as a current limiting or protective device. A relay, on the other hand, is an electromechanical switch used for controlling a circuit but does not serve to limit current directly.

Thus, the fuse fulfills the specific requirement of providing protection by interrupting the circuit under excessive current conditions, making it the correct answer.