A fuse is also called a current fuse, and the IEC127 standard defines it as a "fuse-link". It is mainly used for overload protection. If the fuse is properly placed in the circuit, the fuse will fuse and cut off the current when the current rises to a certain height and heat abnormally, which protects the safe operation of the circuit. When the circuit breaks down or is abnormal, the current will continue to rise, and the rising current may damage some important components in the circuit, or it may burn the circuit or even cause a fire. If the fuse is correctly installed in the circuit, the fuse will fuse and cut off the current when the current abnormally rises to a certain height and heat, thereby protecting the safe operation of the circuit.