The working principle of the fuse

An electrical appliance that uses a metal conductor as a melt to be connected in series in a circuit. When an overload or short-circuit current passes through the melt, it fuses due to its own heat, thereby breaking the circuit. The fuse is simple in structure and easy to use. It is widely used as a protection device in power systems, various electrical equipment and household appliances.
The fuse is mainly composed of three parts: melt, shell and support, and the melt is the key element to control the fuse characteristics. The material, size and shape of the melt determine the fusing characteristics.
Melt materials are divided into two types: low melting point and high melting point. Low melting point materials such as lead and lead alloys have a low melting point and are easy to fuse. Due to their large resistivity, the cross-sectional size of the melt is larger, and more metal vapor is generated during fuse. It is only suitable for fuse with low breaking capacity. Device.
High melting point materials such as copper and silver have high melting points and are not easy to fuse, but due to their low resistivity, they can be made into a smaller cross-sectional size than low melting point melts, and produce less metal vapor during fuse, which is suitable for high breaking Capable fuse. The shape of the melt is divided into two types: filament and ribbon. Changing the shape of the variable cross-section can significantly change the fusing characteristics of the fuse.