Many people find it difficult to accurately determine the positive and negative electrodes of the diode. In fact, the positive and negative electrodes of the diode are very simple.

First of all, you should be clear about which type of device to judge the positive and negative diodes.

Secondly, the specific judgment method of diode positive and negative poles can be used.

This paper takes the fast recovery diode as an example to explain the judgment standard of the positive and negative poles of the fast recovery diode.

Generally, the horizontal bar of the fast recovery diode represents the negative end. If you are afraid of making a mistake, you can use a multimeter to measure and reach the buzzer gear (measure the open circuit gear). Select one end with the positive probe and use the negative probe at the other end. If it is on, it means that the positive probe is positive. If it is not on, replace the two probes to measure and they will definitely be on.

Test the positive and negative poles of the fast recovery diode with a digital multimeter:

If the positive and negative pole marks of the diode are ambiguous, you can use a multimeter to test and judge.

1. Pointer type universal judgment method:

Turn the multimeter to R × For gear 1K, connect the red and black probe to the two electrodes of the diode respectively. The measured impedance in the two directions has a large difference, and the measured resistance is small The black probe is connected to the positive pole of the diode. (Note: When testing with the resistance gear of the multimeter, the positive pole of the battery in the ammeter is connected to the first end of the black probe)

2. Judgment method of digital multimeter:

It can also be measured with the resistance gear 1K, and the measured resistance value is small The black probe should be connected to the negative pole of the diode, because the digital multimeter black probe is connected to the negative pole of the battery.

Most digital multimeters also provide diode test files. The red and black probes are connected to the two electrodes of the diode respectively. One reading is infinite, while the other one has a reading. When the red probe with a reading is connected to the positive pole (A) of the diode.

Note: It may be necessary to separate the diode from the working circuit when testing it.