What is the purpose of a circuit breaker?

The purpose of a circuit breaker is to protect circuits from overloads. When the current flowing through the circuit exceeds the safe limit, the circuit breaker automatically interrupts the circuit to prevent damage to the wiring and connected devices. This is crucial for preventing electrical fires and ensuring the safety of the electrical system. By detecting excessive current, the circuit breaker serves as a safety mechanism that can be reset after the overload condition is resolved, allowing the circuit to be re-energized without the need for replacing a fuse or other components.

Other options describe functions that do not align with the primary role of a circuit breaker. Increasing voltage, regulating alternating current, and improving energy efficiency involve different devices and principles, which do not focus on the protective aspect that a circuit breaker provides.