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

The purpose of a fuse in an electrical circuit is to melt above a specified voltage or current, thereby disconnecting the circuit and preventing excessive current flow. Fuses are designed as a protective device that ensures safety by interrupting the electrical flow when it exceeds safe limits. This helps to prevent damage to electrical components, overheating, and potential fires that can result from overcurrent conditions.

Fuses work based on the principle of thermal effect: when the electrical current flowing through the fuse exceeds its rated capacity, the heat generated causes the metal strip within the fuse to melt. As the strip melts, it creates an open circuit, effectively stopping the flow of electricity.

This function is crucial in protecting both the circuit and its components from damage due to excess current. It is also important to distinguish that fuses do not serve to amplify current, act as a power switch, or reduce voltage levels.