A special device that prevents excessive current from passing through a circuit is a(n) _____.

• A. Circuit breaker
• B. Resistor
• C. Fuse
• D. Relay

Answer: (C)

Overcurrent protection relies on devices that interrupt current when it becomes dangerous. A fuse does this by containing a metal link that melts when the current exceeds its rating, opening the circuit and stopping the flow. This action directly prevents damage by disconnecting the circuit at the moment of overload, and after it blows, it must be replaced. Resistors simply limit how much current can flow but don’t automatically shut the circuit down during a fault. A relay is just a switch controlled by a signal and isn’t in itself a protection device against overload. A circuit breaker also stops overcurrent and can be reset, but the description fits the fuse as the classic protective element that immediately interrupts current when overload occurs.