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need help have a HE 8050C transistor?

Discussion in 'Troubleshooting and Repair' started by jeff2005, May 13, 2010.

  1. jeff2005

    jeff2005

    22
    0
    May 13, 2010
    I have a HE 8050C transistor and the circuit is labed looking a the front of the transistor E,C,B but when i looked up a 8050C transistors datasheet it said something different. how do i test to see which one is what pin where i can see if it a bad transistor?


    thanks
     
  2. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,171
    2,687
    Jan 21, 2010
    Trace the circuit and determine which lead is the base, emitter, and collector that way.

    Most likely, if the transistor is actually labelled with E B and C then that is right. This is no guarantee that another manufacturer will use the same configuration for the transistor leads.

    If the package is even slightly different, no manufacturer will pass up the opportunity to change the order of the leads. I'm sure they believe it creates fun and excitement for people using their products :)
     
  3. jeff2005

    jeff2005

    22
    0
    May 13, 2010
    i think i got a bad transistor here is what i got when i tested the transistor on a MM diode test
    Base to Emitter with postive on base= .658
    postive on emitter= nothing

    Base to Collector with postive on base= .656
    postive on collector= nothing

    Collector to Emitter with postive on Collector= nothing
    postive on emitter= nothing

    do u think the transistor is bad?
     
  4. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Jan 21, 2010
    No, that is exactly what you should see.

    The way you are testing it the transistor will appear to be a pair of back to back diodes connected at the base.
     
  5. jeff2005

    jeff2005

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    0
    May 13, 2010
    ok i was just wondering the readings i got on the collector to emitter was throwing me off because i thought it should conduct one way but not the other, just like the other two test.
     
  6. shrtrnd

    shrtrnd

    3,656
    452
    Jan 15, 2010
    I'll add the obvious, just in case.
    Some manufactures identify transistors from top view, others from bottom view (can sometimes appear reversed). I know at least one of your transistors is marked emitter, base, collector. But make SURE you install the replacement with the same 'polarity'.
    (ie; not reversed in the circuit).
     
  7. Resqueline

    Resqueline

    2,848
    1
    Jul 31, 2009
    To add to the above, which is correct;
    Those 8050 etc. transistors are not universally identifiable (generic numbers) unlike most others. One manufacturer makes them as an NPN and another as a PNP..
    Try to dig for a different datasheet that matches better with your "terrain".
     
  8. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,171
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    Jan 21, 2010
    And to continue with what Resqueline suggests...

    If you can trace the circuit and determine whether the collector of the old transistor is more positive than the emitter (in a simple case one may be tied directly to a supply rail, in a more typical case it may be via a resistor and/or other components).

    If the collector is more positive, then the transistor will be NPN, if it is more negative it will be PNP. Note that transistors are sometimes used in such a way that it may be difficult to determine this easily (just hope yours is a simple case)

    Alternatively, if there is diode action remaining between the base and either the emitter or the collector of the dead transistor, that is unlikely in the extreme to have been reversed by any damage and would be indicative of the transistor's polarity.
     
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