Oilers/Plant Tenders (HHC) Civil Service Practice Exam

A fuse in an electric circuit serves the same function as what other component?

1. Transformer

2. Relay

3. Resistor

4. Circuit breaker

The correct answer is: Circuit breaker

A fuse in an electric circuit is designed to protect the circuit from excess current, which can lead to overheating and potential fires. When the current flowing through a circuit exceeds a certain threshold, the fuse will melt and break the circuit, thereby preventing damage. This mechanism of interrupting the flow of current due to overcurrent conditions is similar to the function of a circuit breaker. A circuit breaker also serves the purpose of protecting the circuit from excess current. However, instead of melting like a fuse, a circuit breaker can be reset once the fault is cleared, allowing the circuit to be reused without needing to replace a component. Both devices are essential for circuit protection but operate under different mechanisms. While transformers, relays, and resistors serve distinct purposes within electric circuits—transformers modify voltage levels, relays act as electrically operated switches, and resistors limit current or divide voltages—they do not function as protective devices against overcurrent conditions in the same manner as fuses and circuit breakers. Therefore, the correct answer highlighting the role of a fuse is its similarity to the function of a circuit breaker in terms of circuit protection.