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General unknown component question

Discussion in 'Datasheets, Manuals and Component Identification' started by MScMech, Aug 4, 2009.

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  1. MScMech


    Aug 4, 2009
    Hi! :confused:

    For an example, I have some transistors from and old phone. Two of them are marked:

    C945 G-811
    C819 S9015

    respectively. I immediately found a data sheet for C945 but nothing about G-811. The one I found seems to be called C945 TO-92, if I understand correctly. Can I assume they are similar? What these are is really not that important right now, but an example of my troubles getting into the world of electronics.

    I have this same experience from previous attempts at identifing electronic components. So I guess my question is if there is a standard for component marking. Or, in practical terms: How do I find a data sheet for any given component marking, and if I find something close, can I tell if I can use it instead?

    I'd be happy if someone could sort this out or point me to a source of knowledge that can.


  2. Resqueline


    Jul 31, 2009
    Tjänare grabben!
    These sounds like japanese transistors.
    You can then just put 2S in front of the markings, so you get 2SC945 & 2SC819.
    The other markings are just factory & date codes. The latter is made in week 15 in 1990.
    Sometimes even the european BC-series are marked in short-hand (C549=BC549).
    You just have to use deduction & recognition to tell the difference.
  3. MScMech


    Aug 4, 2009
    At least that made me a little bit wiser!
  4. JSL


    Aug 28, 2009
    In addition, TO-92 is the type of case ie, little round black plastic things with a flat edge and 3 pins poking out.
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