A circuit breaker is:

A circuit breaker is:

• A. A reusable safety switch that breaks the circuit when the current becomes too high
• B. A device that permanently cuts power when turned on
• C. A resistor that limits current
• D. A device that only works on DC circuits

Answer: (A)

Overcurrent protection is the main idea. A circuit breaker is a device that automatically opens the circuit when the current exceeds a safe limit, stopping the flow to prevent overheating of wiring and reducing fire risk. It’s reusable because after it trips you can reset it and restore power once the fault is fixed. This distinguishes it from a fuse, which would need replacing after it melts. It’s not a resistor that limits current, and while many breakers can handle both AC and DC, their defining feature is the automatic interruption on overcurrent, not the particular type of current.

Overcurrent protection is the main idea. A circuit breaker is a device that automatically opens the circuit when the current exceeds a safe limit, stopping the flow to prevent overheating of wiring and reducing fire risk. It’s reusable because after it trips you can reset it and restore power once the fault is fixed. This distinguishes it from a fuse, which would need replacing after it melts. It’s not a resistor that limits current, and while many breakers can handle both AC and DC, their defining feature is the automatic interruption on overcurrent, not the particular type of current.