The current fuse is an electronic component of the maintenance circuit when it is operated. As a circuit designer, it is necessary to know how to use the fuse to a certain extent. However, from the actual situation, many engineers and designers choose the right one. Current fuses are not very familiar, or even understand. Several elements to consider when choosing.
1. Scale Appearance: Scale Appearance This point is trusted by everyone. The size of the current fuse is mainly determined by the space of the circuit and the installation method of the fuse.
2. Safety certification: The type of current fuse that is certified by the safety regulations is mainly based on which area the finished product is to be exported, and then the fuses corresponding to the safety regulations are selected.
3. Time/current characteristics: The time/current characteristic is the fuse characteristic. There are two types of fast breaking and slow breaking. Which type to choose depends on the maintenance effect of the fuse on the circuit. If required, it can accept larger The impact of the pulse current can maintain the effect when overcurrent. In this case, a slow-break type fuse should be selected. If the circuit is sensitive to current pulses, it is said that the current pulse may damage other components of the circuit, and a fast-break type fuse should be used.
4. Rated voltage: The voltage of the circuit must be less than or equal to the rated voltage of the fuse. If the voltage of the circuit is 125V, then the rated voltage of the selected fuses of 125V and 250V can be used. If the circuit voltage is 250V, only a 250V fuse can be used, and a 125V fuse cannot be used.
5. The normal operating current (IN) of the whole machine: This is the main condition for confirming the selection of the current fuse standard. According to this condition, the standard of the fuse can be confirmed. Considering the difference between actual use and laboratory, the rated current of the selected fuse should be calculated according to the rule formula under the condition of using ambient temperature of 25.
The rated current of the current fuse is confirmed by the test at room temperature of 25 degrees, and the ambient temperature has a great influence on the rated current of the fuse. When the ambient temperature is higher than 25 degrees, the rated current of the fuse will be attenuated. When the temperature is lower than 25 degrees, the rated current value will be "value added".
In the process of manufacturing, the current fuse is mainly composed of three parts. One is the melt part, which is the center of the current fuse. When it is blown, it acts as a blocking circuit. The resistance value is as small as possible and must be together. It is the fuse characteristics to be together; the second is the electrode part, usually two, which is an important part of the melt-circuit connection, it must have excellent conductivity, and no significant device touch resistance should occur.