How To Test A Transistor With Your Multimeter

Today I’m going to show you exactly how to test a transistor with a multimeter to see if they are good or faulty. You can do this with ANY multimeter, yes that’s right. All you need is to be able to select the Ohms setting. This method will only work with PNP of NPN transistors, it will not work with FET transistors.

  1. Plug your leads into your meter, black lead into the common jack and red lead into the Ohms/volts jack.
  2. Set your multimeter to the Ohms on the dial and then if you have the ability to select range on your meter, select a very high range – in the meg-ohms.
  3. Place your transistor on a flat surface in front of you, facing up. From left to right, the pin outs will be Emitter, Base, Collector.
  4. Next, place your black probe on the emitter, and red probe on the base. If you get a reading on your meter, the transistor is good and it’s an NPN transistor.
  5. If you place the black probe on the base and red probe on the emitter, and you get a reading then it’s an PNP.
  6. If you get a reading both ways, then the transistor is likely to be shorted and is faulty.
  7. If you get a reading on your multimeter when testing between the emitter and collector, then your transistor is also likely to be bad.
Place Your Transistor Face Up Like This

It’s that simple! Transistor can be quite fidly to test, due to being such a small component, but once you’ve tested them a few times, you’ll be doing it like a pro. As always, if you have any questions or comments about this article, feel free to send them through and I’ll be happy to get back to you.