What does a circuit breaker do?

A circuit breaker is designed to protect electrical circuits from damage caused by overloads or short circuits. When an electrical fault occurs, such as an overload that exceeds the circuit's safe capacity, the circuit breaker automatically disconnects the circuit. This action prevents the flow of electricity, which helps to avoid overheating, potential fires, or damage to equipment.

The ability of a circuit breaker to interrupt the power supply in response to a fault is crucial for maintaining safety in electrical systems. This protective function ensures that when maximum current levels are exceeded, the circuit is severed, allowing the system to reset once the fault is cleared.

The other choices relate to functions that are not performed by a circuit breaker. For instance, regulating voltage, reducing current flow, or acting as a permanent connection are not characteristics of a circuit breaker. Rather, these roles are typically managed by other devices such as transformers or resistors, respectively.