Which device interrupts current to protect circuits and is typically replaced after fault?

Which device interrupts current to protect circuits and is typically replaced after fault?

• A. Fuse
• B. Circuit Breaker
• C. Transistor
• D. Diode

Answer: (A)

When protecting circuits from overcurrent, the device that opens the path to stop current is key. A fuse works by having a thin metal link that melts if the current exceeds its rating, creating a break in the circuit and stopping the fault current. Because the link is consumed in the process, the fuse must be replaced after it blows. A circuit breaker also interrupts current to protect a circuit, but it trips and can be reset, so it’s not typically replaced after a fault. Transistors and diodes don’t serve as protective disconnects in this sense; they control or rectify current rather than automatically opening the circuit in response to an overcurrent fault.

When protecting circuits from overcurrent, the device that opens the path to stop current is key. A fuse works by having a thin metal link that melts if the current exceeds its rating, creating a break in the circuit and stopping the fault current. Because the link is consumed in the process, the fuse must be replaced after it blows. A circuit breaker also interrupts current to protect a circuit, but it trips and can be reset, so it’s not typically replaced after a fault. Transistors and diodes don’t serve as protective disconnects in this sense; they control or rectify current rather than automatically opening the circuit in response to an overcurrent fault.