Can i test a mosfet with a multimeter??

Thread Starter


Joined Oct 14, 2008
Hi everyone.

I found some testing methods in the datasheets of the mosfets conecrned.
But can i test it with a multimeter whether the mosfet dead r not.

Im thinking that, if a mosfet is dead means, the multimeter must show a conduction between drain to source & source to drain.
Am i right?
And again i have performed another test. see the attachment.
There are three different types of results i got here.
Can anybody clear this.........:(


Case two and three is broken MOSFET.
There is a better way to test these MOSFETS..

Apply 20V gate voltage and let it drive a lamp...

Hehe it seems you've blown some MOSFETS already :D
Before plugging them in you should first have an oscilloscope ready and a couple of multimeters.. To test if the firing sequence is correct..Upper and Lower must never turn on same time :D
Then lastly install the MOSFET once you see proper 20V voltage at the gate to source.



Joined Apr 20, 2004
A meter test is possible. There should be a PN junction between the drain and source leads in reverse polarity to the normally applied voltage. An N channel FET should conduct From the drain to the source, for instance.

All other leads should show no conduction.


Joined Jan 18, 2008
I would expect that if you put the positive lead of you tester on the source and the negative lead on the drain that your LED would light when the part it good.
For an N-channel mosfet, that only shows that the intrinsic diode may be good.

For N-channel, with your meter in the diode check or low ohm position, put the positive lead on drain, negative on source. There should be no conduction. If there is conduction, ground or touch the gate. If it continues to conduct with gate grounded, it is bad. If it does not conduct, then you can test gate operation by briefly touching the positive lead to the gate -- leave negative attached. In doing that, you charge the gate. Then test drain to source conduction. If the mosfet is good, you should see conduction. I then discharge the gate by touching it just to confirm it is working.



Joined Dec 20, 2007
With the gate of the Mosfet floating, it could have the gate capacitance charged and the Mosfet should conduct. Or it can have the gate capacitance discharged and the Mosfet should not conduct.