The method of measuring diode with digital multimeter diode file
Use the diode gear of the digital multimeter to measure the forward and reverse resistance (voltage drop) of the diode to quickly judge the quality of various diodes. The specific measurement method is introduced below.
Measure the forward resistance of the diode.
When measuring the quality of a diode, first adjust the range switch of the digital multimeter to the diode position, and then touch the positive and negative poles of the diode with red and black test leads (generally, the pin with the color ring on the diode shell is the negative pole). For good silicon diodes, the readings displayed by the multimeter are generally in the range of 0.500 to 0.700 (the specific size is related to the type of diode and the test current of the multimeter); for good Schottky diodes and germanium diodes, the readings displayed by the multimeter are generally in the 0.150～0.300. The figure above shows the readings displayed by a multimeter measuring a good silicon rectifier diode.
When measuring the forward resistance of a diode, if the reading displayed by the multimeter is "0.00" or "OL (overflow)", it means that the diode is damaged.
Measure the reverse resistance of the diode.
After measuring the forward resistance of the diode, exchange the red and black test leads, touch the negative electrode of the diode with the red test lead, and touch the positive electrode of the diode with the black test lead, as shown in the figure above. At this time, for good diodes, the readings displayed by the multimeter are generally "OL".
When measuring the forward and reverse resistance of a diode with a multimeter, if the forward and reverse readings displayed by a certain diode are both "0.00" or "OL", it means that the diode is damaged.
