A circuit breaker is an electrical safety device designed to protect an electrical circuit from damage caused by excess current. It functions as a switch that automatically interrupts the flow of electricity when it detects a fault, such as an overload or a short circuit, thereby preventing damage to the circuit, appliances, or electrical system. Circuit breakers are typically found in electrical distribution panels or breaker boxes, where they monitor the flow of electricity to various circuits in a building or structure. When the current exceeds a certain threshold for a specified period, the circuit breaker trips, cutting off the flow of electricity to that circuit.