The specific working principle of the fuse is as follows:
The fuse has a certain resistance. When the current flows through the conductor, it will generate heat. As time increases, the heat generation will increase. The current and resistance also increase the heat generation rate. The structure of the fuse and its installation determine the heat dissipation rate.
If: heat production speed < heat dissipation speed, the fuse will not blow;
If: heat production speed = heat dissipation speed, it will not be blown for a long time;
If: heat production rate > heat dissipation rate, heat accumulation, when the temperature rises above the melting point of the fuse, the fuse will blow.
This is how a fuse works.
In the circuit design, the fuse is connected in series on the power supply side of the circuit. When the load is over-current, the device or the wire is short-circuited, the heat generated by the current reaches the melting point in the part with a small cross-sectional area of the fuse and is fused, protecting the wire of the circuit.