Use a multimeter to measure the forward resistance of the diode, why each gear
The digital multimeter measures the resistance value, converts the analog signal into a digital signal using an A/D conversion chip, and then displays the result. The magnetic head's deflection is how the value is shown on the pointer multimeter. The resistance file test of the diode yielded no resistance values in the forward and reverse directions, however the pointer multimeter test of the same diode yielded resistance in the forward direction, mostly for the following reasons:
Diode Measurements in Circuit Boards
First off, compared to a digital multimeter, the output voltage of the resistance gear on a pointer multimeter is different. The pointer multimeter's maximum output voltage is often 9 volts, while the maximum output voltage of a digital multimeter is typically 3 volts. They differ not only in output voltages, but also in the measuring gears we use and in the output voltages themselves. The digital multimeter's resistance gear has an output voltage range of 1.0 volts to 3.0 volts. When compared to a digital multimeter, the output voltage of the resistance gear on a pointer multimeter is typically higher.
When the output voltage is greater than the diode's voltage drop value, the diode can be turned on. However, when the digital multimeter's voltage drop value is smaller than the diode's voltage drop value, the diode cannot be turned on, which results in infinite forward and reverse resistance when measuring the diode.
It is advisable to select the diode gear when using a digital multimeter to gauge a diode's quality. The digital multimeter's diode gear typically operates at 2.6 volts, which is higher than the diode's forward voltage drop value and enables the diode to be turned on in the forward direction.
The digital multimeter's resistance file can be used to determine whether a diode is leaking by measuring the resistance. At this point, the conclusion should be that the resistance value in the forward measurement has a value, whereas the resistance value in the reverse measurement is infinite. The measurement outcome from the pointer multimeter is also the same. It is evidence that the diode may leak in the opposite direction if the measurement revealed a resistance in the opposite direction.To find it in this instance, we need a specialized equipment. Using a multimeter to determine whether the diode has leakage is inaccurate. Second, because the voltage drop characteristics of the diodes vary, there will also be differences between the results of measuring the diodes using a digital multimeter and the resistance range of the pointer multimeter.In contrast, some special diodes, such as high-voltage diodes, have a relatively large conduction voltage drop of more than 0.7 volts. Since our digital multimeter has a low resistance voltage that cannot cause the diode to pass, the resistance value will appear infinite when measuring. For instance, the typical voltage drop value of silicon tubes and germanium tubes is 0.3 volts to 0.6 volts.
