usually divided into cold and hot resistance. Cold resistance is that the fuse is at 25 ° C, and the resistance value measured by the rated current of less than 10%is used as a rated current. The thermal resistance is transformed by the voltage measurement measured by the full rated current as the test current, that is, R thermal = UD/in. Most fuses are made of positive temperature coefficients, so the general heat resistance is larger than the cold resistance.
The resistance of the fuse is not very important in the entire circuit, but the resistance of the fuse with less than 1 of the Ampel number will be a few o'clock, so this problem should be considered in the low -voltage circuit. In practical applications, the voltage drop is often used in specifications. Let's express the thermal resistance.