I want to check an IGBT FGA25N120ANTD whether it is broken or not. I have a good multimeter.

I followed some online videos I cannot figure out the right way. Could you please help?


2 Answers 2


There are 5 tests you can perform

1) impedance check

Collector-Emitter - should be Megs

Gate-Emitter - should be megs unless internal GE terminator resistor

2) Capacitive check

Gate-Emitter - should be capacitive ... (read further down)

3) Diode check

DMM on diode and Emitter - collector - should be a diode

4) withstand

Megger on 500V (or suitable level for the breakdown voltage BUT less than) Collector-Emitter

5) switch test

20V PSU Collector-Emitter with say... 1A limit, 15V PSU Gate-Emitter - 1st PSU should go into current limit

Do these tests on a known working switch so you know what to expect.

  • \$\begingroup\$ Not sure this is totally clear. What's a Meg? Megger? PSU? Does that terminator resistor really need to come from General Electric? Possible to decode this into plain english, so an average Joe could say... test an IGBT? Question. I see lots of videos online talking about testing an IGBT with 12v battery and lamp. Which of your tests serves as that function? (The fact that I can't tell suggests your descriptions could possibly be improved...or is that a sixth suggested test?) . Thank you for the assistance. \$\endgroup\$
    – zipzit
    May 12, 2017 at 8:12
  • \$\begingroup\$ the answer is fine. Those that know what an IGBT is, know what a PSU is, know what a Megger is, know where the GE is. Please familiarize yourself with an IGBT. Your "average Joe" should not be going near one as these involve 600-1200V \$\endgroup\$
    – user16222
    May 12, 2017 at 9:14

Try a diode check across the collector and emitter. If the IGBT is dead, it should read 0 volts.

  • 2
    \$\begingroup\$ Maybe you could add a little more detail on the test and how it should be performed in some more detail? \$\endgroup\$
    – PeterJ
    Jan 23, 2015 at 12:32

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.