What does a circuit breaker do?

A circuit breaker is a vital safety device in electrical systems that acts to interrupt the flow of electricity in a circuit when it detects an overload or a fault condition. This mechanism is crucial for preventing potential damage to electrical equipment and reducing the risk of fire. When the current exceeds a certain threshold, the circuit breaker automatically opens the circuit, stopping the flow of electricity and thus protecting both the wiring and any connected devices from overheating and potential failure.

The other options do not accurately describe the purpose of a circuit breaker. Amplifying signals pertains to devices like amplifiers, while increasing voltage is the function of a transformer. Connecting different circuits relates to devices such as switches or relays. Therefore, the primary function of a circuit breaker is not about amplifying or adjusting electrical parameters but rather ensuring safety by interrupting electrical flow when needed.