What device is used to protect against overcurrent in electrical circuits?

A circuit breaker is the device used to protect against overcurrent in electrical circuits. Overcurrent occurs when the amount of current exceeds the safe levels that the circuit can handle, which can lead to overheating, damage to equipment, or even fires. The circuit breaker functions by automatically interrupting the flow of electricity when it detects excessive current. This is crucial for maintaining the safety and integrity of electrical systems.

The design of circuit breakers allows them to reset after tripping, making them a reliable choice for protection against persistent overcurrent situations, unlike fuses, which must be replaced once they blow. Their ability to quickly respond to fault conditions makes them essential in both residential and commercial electrical systems for ensuring safety.

Other options serve different purposes: a voltage regulator maintains a constant voltage level, a transformer changes voltage levels to suit different needs, and a capacitor stores electrical energy briefly for various purposes, but none of these provide the protective function that a circuit breaker does against overcurrent situations.