The fuse is also called a fuse, and the IEC127 standard defines it as "fuse link" (fuse-link) ". It is a kind of electrical components installed in the circuit to ensure the safe operation of the circuit.
The role of the fuse is: when the fault or abnormal circuit, with the current increasing, and increase the current may damage the circuit in some important devices or expensive devices, there may even cause a fire burned circuit. If the circuit correctly placed the fuse, the fuse will be so in the abnormal current rises to a certain height and a certain period of time, the fuse, cut off the current, so as to protect the safe operation of the circuit.
(Self recovery fuse)
The working principle of the fuse is: when the current through the conductor, because there are some conductor resistance, so the conductor will heat, and heat follow this formula: Q=0.24I2RT, so the formula we can see that the principle of simple fuse. When the material and the shape of the fuse fuse are determined, the resistance of the fuse R is relatively determined (if the resistance temperature coefficient of the material is not considered). When the current flows through it, it will heat, with the increase of the time the heat is also increased. The size of current and resistance determines the rate of heat generation, the structure of the fuse and the condition of its installation determine the speed of heat dissipation. If the speed is less than the heat generated in the heat dissipation rate, the fuse is not fuse; if the heat generating speed is equal to the heat dissipation rate, in quite a long period of time it will not fuse; if the heat speed is greater than the heat dissipation rate, the heat will be more and more, because it has a certain heat capacity and quality, increase the heat performance in high temperature, when the temperature rises above the melting point of the fuse fuse fuse occurs.
From the electronic related article:
Guide for selection of self - recovery fuses
Self recovery fuse parameters, self recovery fuse symbol specification