Fuse resistance test by multimeter measurement method
A fusing resistor is a special component that serves the dual purpose of a resistor and a fuse. It is represented in the circuit by the letter "RF" or "R".
Selection of Fusing Resistors
Selection should take into account its dual performance, according to the specific requirements of the circuit to select its resistance and power and other parameters. Both to ensure that it can quickly fuse in overload, but also to ensure that it can work under normal conditions for a long time and stable. Resistance value is too large or too much power, can not play a protective role.
In the circuit, when the fuse is open, can be based on experience to make a judgement: if you find the surface of the fusing resistor black or burnt, it can be concluded that it is overloaded, the current through it exceeds the rated value of many times; if the surface of the open circuit without any traces, it shows that the current flowing just equal to, or a little greater than, its rated value of the fuse. For the surface of the fusing resistor without any trace of good or bad judgement, with the help of a multimeter r × 1 block to measure, in order to ensure the accuracy of the measurement, the fusing resistor should be welded from the circuit at one end. If the measured resistance to infinity, the fusing resistor has failed open circuit, if the measured resistance and the nominal value of the difference is very far, indicating that the resistance value, should not be used again. Found in maintenance practice, there are also a few fusing resistors in the circuit is broken short-circuit phenomenon, detection should also be noted.
