What is the function of a circuit breaker?

The function of a circuit breaker is to protect electrical circuits from overloads and short circuits. When the electrical current flowing through a circuit exceeds its safe capacity, a circuit breaker interrupts the flow of electricity, preventing damage to the wiring and appliances connected to that circuit. This automatic disconnection helps to avoid potential hazards such as fires, electrical shocks, or equipment failure.

The circuit breaker achieves this through mechanisms that detect excess current. For instance, it may use thermal or electromagnetic triggers that respond to the level of current. Once the fault is rectified, the breaker can be reset, allowing safe operation again.

In contrast, the other options do not accurately represent the core purpose of a circuit breaker. Increasing electrical current flow is not a function of a breaker, as it is designed to halt excessive flow. Converting AC to DC power is a function of rectifiers or power supplies, not circuit breakers. Acting as a switch for appliances is also inaccurate since while circuit breakers can interrupt power, they are not primarily designed to serve as a simple on/off switch for devices; rather, they serve the vital function of operational safety within electrical systems.