Q: what is the role of the fuse in the circuit?
A: it is very simple, the role of the fuse is in the case of short-circuit or overload and so on when the fuse to cut off the circuit to protect the electrical components protected by the fuse. The fuse is made of an insulated shell, a wire that has an interface!
The resistance of a household fuse is generally rated as XX amperes and printed on the fuse tube. Generally the resistance of household fuses 20CM 2MM*2MM.
The fuse is also known as a fuse, which is defined by the IEC127 standard as a "fuse" (fuse-link)". The utility model relates to an electric appliance component which is arranged in a 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 increases to a certain height and a certain time, the fuse cut off the current, so as to protect the safe operation of the circuit. The first fuse was invented by Edison more than and 100 years ago, because of the industrial technology is not developed at the time of the incandescent lamp is very valuable, so it was originally used to protect the price of incandescent lamps.
As we all know, when the current flows through the conductor, the conductor has a certain resistance, so the conductor will heat. And heat follow this formula: Q=0.24I2RT; Q is the heat, the 0.24 is a constant, I is the current flowing through the conductor, R is the resistance of a conductor, T is the current through the conductor time; so the formula we can see that the principle of simple fuse.
When the material and the shape of the fuse are determined, the resistance R is relatively fixed (if the temperature coefficient of resistance is not considered). When the current flows through it, it will heat, with the increase in the amount of heat is also increasing. The size of the current and the resistance heat generating speed, fuse structure and its installation condition to determine the heat dissipation rate, if the speed is less than the heat generated in the heat dissipation rate, the fuse is not fuse. If the rate of heat generation is equal to the rate of heat dissipation, it will not be blown for a long time. If the rate of heat generation is greater than the rate of heat dissipation, the heat will be increased. And because it has a certain specific heat and mass, the increase in heat is reflected in the increase in temperature, when the temperature rises above the fuse fuse fuse fuse. This is how the fuse works. You should know from this principle that you must carefully study the physical properties of the materials you have chosen for the design and manufacture of fuses and make sure they have the same geometric dimensions. These factors play an important role in the normal operation of the fuse. Also, when you use it, be sure to install it correctly.