Help me identify this transistor

Discussion in 'General Electronics Chat' started by sp00nix, Aug 6, 2011.

  1. sp00nix

    Thread Starter New Member

    Apr 10, 2010
    5
    1
    I'm trying to diagnose a PWM circuit and it has a transistor that i cannot find any info on. I tried to google without luck. Only markings is has are J348 and 4D1.

    Thanks!

    [​IMG]

    Edit: Added image
     
    Last edited: Aug 6, 2011
  2. bertus

    Administrator

    Apr 5, 2008
    15,647
    2,346
    Hello,

    It is most probably an 2SJ248, a fast switching Mosfet.
    (very often the 2S is ommitted).
    (see attached datasheet).

    Bertus
     
  3. sp00nix

    Thread Starter New Member

    Apr 10, 2010
    5
    1
    Ah thank you my good man. I get no reading between the gate and any other pin on my ohm meter. Would this suggest this is bad?
     
  4. #12

    Expert

    Nov 30, 2010
    16,278
    6,791
    The gate is supposed to be high resistance to all other terminals. No problem.
     
  5. sp00nix

    Thread Starter New Member

    Apr 10, 2010
    5
    1
    Heh, i put it all back together and it works now :). I guess there was some bad solder joints.

    Thanks for the info, at least i came out knowing a bit more :)
     
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