A Fuse is an electronic\electric component that is used to protect circuits against high currents. It consist out of a class tube, two metal terminals on the ends and a fuse wire running between the two terminals inside the class tube. The fuse wire is rated for a specific voltage and current rating and these values are normally printed or engraved on one of the metal terminals. A fuse is used to protect electrical circuits from the damage high currents can cause when something goes wrong in the circuit and too much current is drawn. When the current flowing through the fuse reaches the current rating of the fuse, the fuse wire is burned off disconnecting the power source from the electronic circuitry. If a fuse weren’t present the whole circuit might burn out causing a lot more damage than one faulty component.
Fuses are used in all electrical circuits normally in the power supply circuit to protect electronic equipment from the damage caused by high currents.