How to Test a MOSFET

Discussion in 'General Electronics Chat' started by Jotto, Apr 21, 2011.

  1. Jotto

    Thread Starter Member

    Apr 1, 2011
    Would have posted this in tips but its locked.

    Testing a MOSFET is very easy, going to use a K2698 for the example. This is a good part for two reason, one you will see how to test one, two its a part number that sometimes you need to add a little more information to get the correct part.

    Manufactures leave off some of the information sometimes, before if you didn't know this you would never find the part (an then came the internet).

    I know from experience dealing with this for many years, K2698 wouldn't have been a good number. But if you added 2sk2698 you would have found what your looking for. This doesn't happen a lot, but it good to know if you can't find the correct sub. There are a few more that I know of, but that is for another time.

    Now to test the component.

    1 - Gate
    2 - Drain
    3 - Source

    1. Neg to pin 2, pos to pin 3 should read like a diode.
    2. Remove positive from pin 3 and touch pin 1, and then back to pin 3, now its shorted to act like the switch. Over time it will discharge and read like a diode again.
    3. To release the short, Neg from pin 2 to pin 1. Now its back to a diode.

    This is a good test for the MOSFET, I used this as an example because its a big one and will bleed off rather fast, an of course I have some.