The function of the circuit breaker corresponds basically to that of

• A. a switch in combination with a fuse
• B. a resistor and a capacitor
• C. a relay alone
• D. a transformer

Answer: (A)

A circuit breaker protects by automatically interrupting current when something wrong happens, acting like a switch that can open the circuit, and it does this in a way that mirrors a fuse’s ability to stop current. The combination captures the two key ideas: you can disconnect the circuit (switching action) and you can interrupt excessive current to prevent damage (fuse-like protection). The other options don’t fit: a resistor and a capacitor form filtering or timing elements, not protection; a relay alone is just a controlled switch without inherent overcurrent protection; a transformer changes voltage/current, not the ability to disconnect the circuit.