What is the main function of a circuit breaker?

The main function of a circuit breaker is to automatically interrupt electrical flow. This is crucial for protecting electrical circuits from overload and short circuits, which can lead to overheating and potential fire hazards. When the current flowing through the circuit exceeds a certain threshold, the circuit breaker detects this abnormal condition and quickly opens the circuit, effectively stopping the flow of electricity. This automatic response is vital for maintaining safety in electrical systems by preventing damage to equipment and reducing the risk of electrical fires.

The other options are related to different aspects of electrical systems but do not describe the primary function of a circuit breaker. Voltage regulation refers to maintaining a constant voltage level, increasing circuit current does not align with the protective role of a breaker, and connecting multiple circuits together pertains more to circuitry design and functionality rather than overload protection.