What is a circuit breaker?

• A. A resistor used to limit current in a circuit.
• B. A light switch that can be toggled manually.
• C. A protective device that automatically interrupts current flow when an overload or fault occurs.
• D. A device that stores electrical energy for later use.

Answer: (C)

A circuit breaker is a protective device that automatically interrupts current flow when there is an overload or fault. It senses excess current and trips, opening the circuit to prevent overheating, damage, and fire. After the issue is resolved, you can reset the breaker to restore power. This automatic protection sets it apart from a resistor, which only limits current; a manual light switch, which is operated by hand and isn’t meant to trip automatically; and from devices that store energy, which aren’t designed to protect the circuit.