Mini fuses are mainly used in digital cameras, notebook computers, mobile phones and other electronic products. From traditional glass tube fuses to miniature fuses, because of the difference in product technology, their selection points are also slightly different. The selection of miniature fuses touches the following elements:
1. The normal operating current of the circuit should not exceed 75% of the rated current of the fuse.
2. Pulse, pulse current, surge current, starting current and circuit transient value. Miniature fuses pay special attention to this. Because of the technical reasons brought about by the small scale, the impact resistance of the miniature fuse is much lower than the impact resistance of the glass tube fuse or other larger fuses with the same rated current.
3. The size of the overload current and the shortest and longest moment of the overload current in the circuit generally need to be judged by the oscilloscope test and theoretical calculation to determine the size of the overload current. The basic requirement of fuses is that they should not be interrupted at any time, and should be interrupted at an appropriate time.
4. The resistance of the miniature fuse has a certain effect on some circuits: if a fuse with an excessively large internal resistance is installed in some circuits, it will affect the system parameters of the circuit and make the circuit not work normally;
5. The ambient temperature of the fuse, when the miniature fuse is used in the portable equipment, the temperature rise of the fuse should be considered, that is, the decrease of the fuse's rated current. The ambient temperature of the fuse should be within the regular operating temperature range. When the ambient temperature around the fuse exceeds 25 ° C, the temperature should be decreased according to the temperature decrease curve.
6. The applied voltage applied to the fuse is generally applied to portable equipment. The operating voltage of the circuit is generally not high. As long as the rated voltage of the miniature fuse is higher than the operating voltage of the circuit, it can be safely selected.
7. Product certification, such as export to North America, must pass UL or CSA certification. Now, products exported to Europe also need to comply with the EU ’s RoHS directive, which is generally called SGS and other environmental certifications.