Fuse (fuse) is an electrical appliance that breaks a circuit when the current exceeds a specified value by fusing the fuse with the heat generated by itself. Its working principle is based on the thermal effect of the current, that is, when the current through the conductor, due to the existence of a certain resistance of the conductor, so it will produce heat. When the current is too large, the heat generated is enough to make the melt (usually made of metal or alloy) to reach the melting point and fuse, thus cutting off the circuit and preventing the current from continuing to cause damage to the circuit and equipment.

Fuses are widely used in high and low voltage power distribution systems and control systems as well as electrical equipment, as a short circuit and overcurrent protector. It is one of the most commonly used protection devices, which is of great significance in safeguarding the normal operation of circuits and equipment. In the power system, the fuse can quickly cut off the faulty circuit, preventing the fault from expanding and causing greater accidents. In the electrical equipment, the fuse can protect the equipment from overload and short-circuit current damage, prolong the service life of the equipment.