Diodes Test Procedure

Diode: A semiconductor device that only allows current to pass through it in one direction, cathode to anode. Most diodes are made with semiconductor materials such as silicon, germanium, or selenium.Examples: Rectifier, Zener, LED, Varactor, Photodiode and Tunnel diodes.

Diodes Test Working Procedure:

* To test a Diode, use a Digital Multimeter (Here we used “Fluke Multimeter”).

* Set the knob Diode scale (Shown in Fig)

* Make sure you have isolated the Diode from running circuit (for old Diodes).

* Connect the red lead (meter positive terminal) to diode anode. Connect the black lead (meter negative terminal) to diode cathode. If the meter reading 0.3 to 0.8 Volts dc, the diode is ok.(Fig-1)

* Connect the red lead (meter positive terminal) to diode cathode. Connect the black lead (meter negative terminal) to diode anode. If the indicating “out of range” or O.L , the diode is ok. (Fig-2)

* If the meter reading 0.01 or short or both side open (out of range) the Diode faulty (burned or shorted)

For Zener Diode, we can use a Ohmmeter and check resistance across the diode. The resistance should be higher than 15K-Ω.


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