What function does a circuit breaker serve?

A circuit breaker is essential for protecting electrical circuits from overcurrents that can cause damage or hazards such as electrical fires. When excess current flows through the circuit—typically due to a short circuit or overload—the circuit breaker detects this condition and automatically interrupts the flow of electricity. This action helps to prevent potential damage to wires, devices, and other components connected to the circuit, thereby safeguarding both the equipment and the individuals using it.

The other functions listed do not accurately describe what a circuit breaker does. Enhancing voltage stability, increasing current flow capacity, and stepping down voltage levels are tasks typically associated with transformers, voltage regulators, and other equipment rather than the primary function of circuit breakers.