2007-12-19 03:46:39 · 8 answers · asked by Anonymous in Science & Mathematics ➔ Engineering
You can use a DVM, but you have to use the DIODE selection on the meter. A normal DVM ohms position will not forward bias the diode junction. The DIODE selection uses the 9V battery to ensure that you turn on the diode. You should see about .7v forward and a virtual open circuit the other direction.
2007-12-19 05:13:19 · answer #1 · answered by Warren W- a Mormon engineer 6 · 0⤊ 0⤋
How To Test A Diode
2016-09-30 23:21:56 · answer #2 · answered by ? 4 · 0⤊ 0⤋
The most trivial means of testing a diode is with the diode test function of a typical digital multimeter. Most small-signal diodes (and many power diodes) can be tested in this manner. Apply the leads both ways and make sure that conduction is from anode to cathode only, and that the measured voltage drop is 'good' based on a good part (or the recommendations of the data sheet)
Bear in mind that there exist some high-current diodes (some power Schottky rectifiers, for example) that exhibit enough reverse leakage that they may appear to be bad when tested with a DMM (since the test current is very low). I test these sorts of parts with a current-limited DC power supply - hook the part up both ways with the supply set to a few amps, and make sure that there is minimal conduction in the reverse direction.
2007-12-19 05:47:30 · answer #3 · answered by angstful_mfg_employee 1 · 0⤊ 0⤋
You need a multimeter with a diode test setting. If you connect the black lead (negative) to the side of the diode with the line on the end and the red lead (positive) to the other side of the diode, the meter should show about 0.6. If you reverse the leads of the meter it should read nothing i.e open circuit. Diodes normally fail open or short circuit. If you get any other reading on the meter the diode is faulty. The best is to check your meter first with a good known diode to verify the correct meter reading.
2007-12-19 03:55:56 · answer #4 · answered by Anonymous · 0⤊ 0⤋
Any ohm meter, digital or swing, will do. Diodes should conduct in one direction and not in the other. Easy. And a working pnp transistor will test like two diodes back to back.
Have fun!
2007-12-19 03:53:22 · answer #5 · answered by Ken 7 · 0⤊ 0⤋
how to test bad diode
2016-07-12 15:56:00 · answer #6 · answered by Shakira 1 · 0⤊ 0⤋
A diode conducts in one direction only so any continuity tester will work.
Diodes usually go short (conduct in both directions) when they go bad. Not always, of course.
2007-12-19 03:55:13 · answer #7 · answered by Poor one 6 · 0⤊ 0⤋
I would use a DMM and check for continuity. I have seen some that have special diode testers in them that will tell you if it's working properly.
2007-12-19 03:48:47 · answer #8 · answered by SPUD 2 · 0⤊ 0⤋