What is the primary function of a fuse in an electrical circuit?

The primary function of a fuse in an electrical circuit is to protect the circuit from excessive current. Fuses are safety devices designed to melt and interrupt the flow of electricity when the current exceeds a predetermined level. This interruption helps prevent overheating, potential fires, and damage to appliances and other components in the circuit.

When the current flowing through the fuse exceeds its rated capacity, the fuse wire heats up and eventually melts, breaking the circuit. This protects not only the wiring and devices connected to the circuit but also ensures safety by minimizing the risk of electrical fires caused by overloaded circuits.

In contrast, the other options—conversion of AC to DC, regulation of voltage levels, and measuring current flow—do not align with the primary role of a fuse. Those functions are typically handled by other components like rectifiers, voltage regulators, and ammeters, respectively.