What is the primary function of a circuit breaker?

The primary function of a circuit breaker is to automatically switch off electrical circuits to prevent overload or short circuit. Circuit breakers are essential safety devices found in virtually every electrical system. They monitor the flow of current and can detect when there is an excessive current flow that could indicate an overload or a fault condition. When such a condition is detected, the circuit breaker interrupts the flow of electricity, effectively shutting down power to that circuit. This immediate action protects the wiring and connected devices from damage, reduces the risk of electrical fires, and enhances overall safety.

The other options do not describe the primary purpose of a circuit breaker accurately. Increasing voltage pertains to transformers or devices specifically designed for that function. Regulating current could involve various devices like resistors or voltage regulators, but not circuit breakers, which do not modify the electrical parameters of the circuit they protect. Connecting different electrical systems typically refers to different kinds of switchgear or merging devices, not the protective function of a circuit breaker.