What does a circuit breaker do?

A circuit breaker serves a critical safety function in electrical systems by interrupting the flow of electricity when it detects an overload or short circuit. This is essential for preventing damage to wiring and appliances, as well as reducing the risk of electrical fires. When too much current flows through the circuit, the circuit breaker automatically trips, cutting off the electrical supply. This mechanism protects both the electrical system and the devices connected to it from potential harm.

The other options describe different electrical functions that are not associated with a circuit breaker. Amplifying electrical signals refers to devices like amplifiers, while voltage regulation is typically handled by regulators or transformers. The conversion of AC to DC is performed by rectifiers, not circuit breakers. Therefore, the unique role of a circuit breaker in interrupting and controlling current flow to ensure safety is what makes this option the correct choice.