Which protective device melts its internal element to interrupt the circuit?

Which protective device melts its internal element to interrupt the circuit?

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

Answer: (A)

A fuse is the protective device that interrupts the circuit by melting its internal element when the current becomes too high. That melting creates an open path, stopping all current flow. It’s a one-time protective device: once it blows, you replace it. In contrast, a circuit breaker interrupts by tripping a mechanism that opens the contacts, and it can be reset after the fault is cleared. Resistors and capacitors don’t serve this protective interrupting role: a resistor primarily limits current and can overheat or fail if overloaded, while a capacitor stores energy and isn’t designed to interrupt a fault current.

A fuse is the protective device that interrupts the circuit by melting its internal element when the current becomes too high. That melting creates an open path, stopping all current flow. It’s a one-time protective device: once it blows, you replace it.

In contrast, a circuit breaker interrupts by tripping a mechanism that opens the contacts, and it can be reset after the fault is cleared. Resistors and capacitors don’t serve this protective interrupting role: a resistor primarily limits current and can overheat or fail if overloaded, while a capacitor stores energy and isn’t designed to interrupt a fault current.