What device acts as an automatic switch to interrupt a circuit when current exceeds safe levels?

A circuit breaker serves as an automatic switch that interrupts a circuit when the current flowing through it exceeds safe levels. It is designed to protect electrical circuits from damage caused by overloads or short circuits. When the current reaches a predetermined level, the circuit breaker trips, effectively opening the circuit and stopping the flow of electricity. This prevents overheating, reduces fire hazards, and protects the connected appliances and devices from possible damage due to excessive current.

While a fuse also interrupts the circuit when current exceeds safe levels, it does so by melting a metal wire or strip within it, leading to permanent disconnection until the fuse is replaced. A circuit breaker, on the other hand, can be reset and reused after tripping, making it more convenient and practical for modern electrical systems. Resistors and transistors, while important components in electrical circuits, do not serve the function of interrupting current in the case of overloads.