A diode is a semiconductor device with unidirectional conductivity. It can be measured with a multimeter. The main check is whether its unidirectional conductivity is normal, so as to judge the quality of the diode. What is the specific operation?
1. Insert the black test lead on the multimeter into the "COM" jack of the common terminal, and the red test lead into the "Ω/V" jack.
2. Turn the gear switch to "Diode with buzzer gear", and press the power switch of the multimeter. When "1" is displayed on the screen, the test can be started.
3. Use the positive electrode of the diode to contact the red test pen, and the negative electrode to contact the black test pen. At this time, the forward resistance value of the diode is displayed on the screen, which should be around 500Ω-700Ω under normal circumstances.
4. Swap two pens for reverse test. Since the diode is reversely cut off at this time, the initial symbol "1" is displayed on the screen, indicating that its reverse resistance value is "m". This condition indicates that the diode is good.
5. If the diode is exchanged for forward and reverse tests, the results are both "1" or "0", or the reverse test shows that it is not "1", etc. These conditions indicate that the diode is damaged and can no longer be used.
