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help identify these transistors

Discussion in 'Misc Electronics' started by sreenath, Oct 29, 2005.

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  1. sreenath

    sreenath Guest

    Hi all,

    A few years ago (1995) I bought a scoop of plastic transistors from
    a company called "electronic goldmine". I am unable to get any data
    on these transistors.

    Can anyone please identify these transistors?

    All are plastic, small signal packages, I think to-92 type.

    1. national semiconductor. marking "615-3"

    2. national semiconductor. marking "2553"

    3. national semiconductor. marking "435-1"

    In addition, all of these also have another number like "827",
    "826", but I think they are the year of marking and month/quarter,
    etc. Apart from these two, there is nothing else printed on the

    Curioucly, there is a three color band coding on the back of the
    I dnot know if this indicated a current gain factor or something.

    Thanks in advance,
  2. Mike Berger

    Mike Berger Guest

    The numbers on the packages are meaningless. They're house
    numbers. The color code will give you the part number. It's
    just like the resistor color code.
  3. sreenath

    sreenath Guest

    thanks for the tips. I tried using the color codes,and could not find
    meaningful results.

    There are three colors on the back of the transistor. Also, after I
    don't have any way of knowing what the preceding type would be, like
    2N, MPS, 2SC, etc.

    I am really consufed. Don't know why a company like National
    semiconductors does like this- not printing the full device type on the

  4. Mike Berger

    Mike Berger Guest

    If they're National, they're probably 2N numbers.
  5. There is a reason: if those transistors were produced with some special
    specifications for one single customer. In common those transistors have
    uncommon type numbers.

    On the other hand, there may be a solution for your problem. When you
    look into an old NS transistor data book, you won't find detailed data
    for type numbers - you'll find them for processes! Of course there is a
    table with some 'coarse' data for National's transistor types (like
    but details can be found under "process 19". Perhaps the colour marking
    corresponds to the number of the process.


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