What is the purpose of a circuit breaker in electrical systems?

A circuit breaker serves the essential function of interrupting the flow of electricity in a circuit when it detects a current level that exceeds a predetermined limit. This occurs in situations where there is a fault—such as a short circuit or an overload—that could potentially lead to overheating and fire hazards. By automatically breaking the circuit when current is too high, the circuit breaker ensures safety by preventing damage to the electrical system and reducing the risk of fire.

Understanding the other options helps clarify why they do not represent the primary purpose of a circuit breaker. While increasing current flow or enhancing mechanical protection might seem useful in certain scenarios, these functions are not associated with the operation of a circuit breaker. Furthermore, protecting against voltage drop is not relevant to the circuit breaker's role, as it is specifically designed to respond to current levels rather than voltage levels.

In summary, a circuit breaker is critical for maintaining safety in electrical systems by disconnecting the supply when excessive current demands are detected, thus mitigating potential risks associated with electrical faults.