How does a fuse protect a circuit?

A fuse protects a circuit by opening during overcurrent conditions. This mechanism is crucial for preventing damage to electrical components and wiring due to excessive current flow. When the current exceeds the fuse's rated capacity, the heat generated by the increased current causes the metal conductor within the fuse to melt. This melting creates a break in the circuit, interrupting the flow of electricity and effectively stopping the current.

This protection method is vital in ensuring that devices and wiring in the circuit are safeguarded against potential overheating and potential failure. By disconnecting the circuit in the event of overcurrent, the fuse helps to maintain the safety and integrity of the electrical system. Other options such as increasing current, reducing voltage, or shorting the circuit do not provide effective protection and could lead to hazardous situations.