A circuit breaker is an electrical device designed to protect an electrical circuit from damage caused by overload or short circuit. It automatically interrupts the flow of electricity when it detects a fault, preventing potential hazards like fires or equipment damage. Circuit breakers can be reset manually or automatically after the fault is cleared. These devices come in various types, including miniature circuit breakers (MCBs) and residual current devices (RCDs), each serving specific functions. They are essential components in residential and commercial electrical systems, ensuring safety and reliability in the use of electrical appliances and equipment.