Diġitali multimeter reżistenza firxa ittestjar dajowd
A diġitali multimeter jikkonverti il imkejjel reżistenza valur fi a diġitali sinjal permezz an A/D konverżjoni chip, u imbagħad displays ir-reżistenza valur. A pointer multimeter displays il - valur billi deflecting il manjetiku ras. If in attwali kejl, we find that using a digital multimeter to test the resistance range of a diode has no resistance value in both the forward and reverse directions, filwaqt using a pointer multimeter to test the diode has resistance value in the forward direction, there are mainly the following reasons:
Diode kejl in circuit boards
Firstly, the output voltage of the resistance range of a pointer multimeter and a digital multimeter is different. Generally, the maximum output voltage of a pointer multimeter is 9 volts, while a digital multimeter generally has a maximum output voltage of 3 volts. At the same time, not only do they output different voltages, but we choose different ranges when measuring, and the output voltage of the resistance range of a digital multimeter varies from 1.0 volts to 3.0 volts, The resistance output voltage of a pointer multimeter is generally higher than that of a digital multimeter. The output voltage of a pointer multimeter is greater than the voltage drop value of the diode, and the diode can conduct. However, sometimes a digital multimeter is smaller than the voltage drop value of the diode, causing the diode to not conduct. This can cause infinite forward and reverse resistance values when measuring the diode.
Secondly, the voltage drop characteristics of the second stage transistor are different, li can also cause deviations in the results of measuring the second stage transistor using a pointer multimeter resistance level compared to using a using a using a digital multimeter to measure the second stage transistor. For example, silicon and germanium tubes generally have a voltage drop value between {{{{0}.7d.3 volts and 0}}}}}}.7d.3 volts and 0. 6 Volts, imma xi wħud aktar speċjali sekonda stage transistors, such as high-voltage diodes, have a larger conduction voltage drop and generally need to reach 0.7 volts or more, filwaqt li tagħna digital multimeter resistance level voltage is lower, It is is mhux possible to conduct the diode, so it will cause the resistance value to appear infinite during measurement.
When measuring the quality of a diode with a digital multimeter, it is best to choose the diode gear. The diode gear of a digital multimeter is generally around 2.6 volts, li is generally greater than the forward voltage drop value of the diode, and the diode, and the diode conduct in both directions.
If we want to use a resistance range to measure whether there is leakage in the diode, we can choose a digital multimeter resistance range. At this point, the result should be a resistance value in the forward measurement, an infinite resistance value in the forward measurement, an infinite resistance value in the reverse measurement, and the result of a pointer multimeter measurement is the same. If a resistance value is found in the reverse measurement, it indicates li id-dijodu jista' have leakage in the reverse direction. In this case, we need to use specialized instruments to detect it, It is not accurate to use a multimeter to measure jekk hemm hemm tnixxija f'dan dijodu.
