Which circuit component is primarily used to interrupt current flow in the event of an overload?

• A. Switch
• B. Fuses
• C. Relays
• D. Capacitors

Answer: (B)

Overload protection relies on a device that automatically stops current when it’s too high. A fuse does this by containing a metal link that melts when the current exceeds its rated value. That melting opens the circuit, halting current flow and protecting wiring and components from overheating or fire. The rating is chosen to be just above normal operating current, so it stays closed during normal use but opens under fault conditions. Some fuses act quickly for fast protection, while others tolerate short surges but still open on a sustained overload; they’re usually single-use and must be replaced after they blow.

A switch is for manual control and doesn’t inherently respond to overload. Relays are control devices that open or close circuits under electrical control, not primarily protective elements. Capacitors store energy and help manage voltage and current in circuits; they don’t interrupt current to protect against overload. So the fuse is the component designed to interrupt current flow when an overload occurs.