What is the primary function of a circuit breaker?

A circuit breaker is designed primarily to interrupt the flow of electricity in a circuit during overload conditions or in the event of a fault, such as a short circuit. When the electrical current exceeds the safe threshold, the circuit breaker automatically opens, breaking the circuit and preventing excessive heat build-up and potential damage to the wiring or connected devices. This interruption is crucial for protecting electrical systems from fire hazards, equipment damage, and ensuring safety for users.

The other options, while related to electrical systems, do not accurately reflect the primary purpose of a circuit breaker. Enhancing electrical flow is not a function of a circuit breaker; instead, they focus on safety by controlling and maintaining flow conditions. Measuring voltage is the role of a voltmeter or similar device, which provides information about electrical potential but does not interrupt current flow. Increasing circuit capacity is something that might be achieved by different means, such as upgrading the wiring and components, but again, it is not the role of a circuit breaker to do this.