Can anyone identify this transistor?

Discussion in 'General Electronics Chat' started by Spence E, Apr 13, 2015.

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  1. Spence E

    Thread Starter New Member

    Apr 13, 2015
    Trying to diagnose the AC controls on my car. Took the unit out and came across a transistor that read faulty after removing from the circuit. From the research I've done, I'm to believe it's an NPN transistor as that's how it tested. Got a TIP31AG transistor from radioshack. Appears to work, but I don't get the 12v from the transistor that is needed. Any help would be greatly appreciated. 20150412_221722.jpg
  2. ian field

    AAC Fanatic!

    Oct 27, 2012
    The A separated from the rest of the number threw me a bit, but it could be a 2SA part - Asian manufacturers usually leave out the 2S part of the number.

    Transistors starting with 2SA are usually PNP, and some manufacturers encapsulate PNP parts in that funny blue/green epoxy - but some manufacturers pot their transistors in weird & wonderful colours, so colour isn't an absolute guarantee of polariry.
  3. Spence E

    Thread Starter New Member

    Apr 13, 2015
    Thanks for the reply. That is interesting. Its also printed on the bottom of the circuit B C E where the transistor goes.
  4. MikeML

    AAC Fanatic!

    Oct 2, 2009
    8651 looks like a date code: 1986, 51st week of the year.
    Most automotive parts are "house numbered", so you cannot find data sheets or cross-reference.
  5. #12


    Nov 30, 2010
    I tried the 2SA and got nothing.
    This is part of the automotive controls and I fear to participate because it is against the rules of the site.
  6. Spence E

    Thread Starter New Member

    Apr 13, 2015
    Automotive circuits are against the rules here?
  7. ScottWang


    Aug 23, 2012
    Welcome to the AAC forum.

    The owners of All About Circuits has elected not to host discussions of automotive electrical system modifications/enhancements due to safety concerns, the potential of legal ramifications and the possible circumvention of vehicle regulations at the state and federal level.

    This thread is against the AAC forum rules, Terms of Service (ToS).

    Any kind of over-unity devices and systems
    Automotive modifications
    Devices designed to electrocute or shock another person
    LEDs to mains
    Phone jammers
    Rail guns and high-energy projectile devices
    Transformer-less power supplies
    Terms of Service (ToS).

    Automotive modifications of any kind are strictly forbidden. Therefore, this thread will be closed.

    Please try to understand the reasons behind this action, and feel free to browse and use the forums.

    You might find answers to your questions in one of these forums:

    Another good forum that shares many of the same membership is .

    Good luck.
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