Which of the following is NOT a type of circuit protection device?

• A. Fuse
• B. Surge protector
• C. Power supply
• D. Circuit breaker

Answer: (C)

Understanding circuit protection means recognizing which components guard the circuit against faults versus those that supply power. Fuses protect by melting open when current gets too high, interrupting the circuit to prevent overheating. Surge protectors respond to voltage spikes, diverting or clamping excess voltage to keep connected devices safe. Circuit breakers act like switches that automatically trip and open the circuit when an overcurrent or fault is detected. A power supply’s job is to provide the necessary voltage and current to run the system; it is not primarily a protective device. So the item that is not a circuit protection device is the power supply.