What is the purpose of a fuse in an electrical circuit?

A fuse serves a critical safety function in an electrical circuit by protecting it against overcurrent situations. When the current flowing through the circuit exceeds a designated level—often due to a fault or malfunction—the fuse will heat up and melt, effectively breaking the circuit. This interruption prevents excessive heat buildup that could lead to wire insulation melting, component damage, or even electrical fires.

Understanding the role of a fuse is essential in both residential and industrial electrical systems, as it helps ensure the longevity of electrical components and the safety of users by mitigating the risk of faults leading to more severe incidents. The other options, while related to electrical concepts, do not represent the primary function of a fuse in a circuit: fuses do not increase voltage, provide a permanent current path, or act as switches. Their sole purpose is dedicated to current protection.