The fuses used in power circuits and high-power equipment not only have three parts of the general fuse, but also arc extinguishing devices, because the circuit protected by such fuses not only has a large operating current, but also two when the melt is blown. The voltage at the terminal is also very high, and the melt tends to melt (fuse) or even vaporize, but the current is not cut off. The reason is that under the action of voltage and current, the two electrodes of the fuse are pulled between the fuses. Arc phenomenon. This arc extinguishing device must have strong insulation and good thermal conductivity, and is negatively charged. Quartz sand is a commonly used arc extinguishing material.