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

The primary function of a fuse in an electrical circuit is to disconnect the circuit during overload conditions. A fuse is essentially a safety device designed to protect electrical circuits from excessive current that can lead to overheating, which could potentially cause fires or damage to components. When the current flowing through the fuse exceeds its rated capacity, the wire inside the fuse heats up and melts, breaking the circuit and stopping the flow of electricity. This action helps protect the overall electrical system and any connected devices from harm.

The other options involve functions that do not accurately describe a fuse's purpose. Increasing voltage, regulating current, and amplifying signals are roles played by other electrical components like transformers, resistors, or amplifiers, rather than fuses. These components serve distinct and separate purposes that do not contribute to the protective function that a fuse provides in a circuit.