Question about the right transistors

Discussion in 'General Electronics Chat' started by lubnaan90, Jan 13, 2010.

  1. lubnaan90

    Thread Starter Active Member

    Jan 13, 2010
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    Can any one plzzzzzzz tell me, which transistors (Q1-Q10) are used in the "Oscillator, counter & decoder, and VU-LED" schematic , the picture is attached for reference . it seems the author forgot to mention the same in the Schematic .
     
  2. SgtWookie

    Expert

    Jul 17, 2007
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    You are "hijacking" someone else's topic. Please start a new topic instead of jumping in the middle of someone elses' topic, as it creates confusion.

    To answer your question, you could use any general purpose PNP transistor. 2N2907, 2N3906, 2N4403, and a variety of others would work fine.
     
    Last edited: Jan 14, 2010
  3. beenthere

    Retired Moderator

    Apr 20, 2004
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    I have moved your question to it's own thread.
     
  4. lubnaan90

    Thread Starter Active Member

    Jan 13, 2010
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    thnx a lot 4 ur help , sorry abt the hijacking , will note ur point .
     
  5. lubnaan90

    Thread Starter Active Member

    Jan 13, 2010
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    Thank you for the same.:)
     
  6. lubnaan90

    Thread Starter Active Member

    Jan 13, 2010
    196
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    Cant find Transistor 2N3643 NPN , can suggestions for an equivalent transistor ?
     
  7. SgtWookie

    Expert

    Jul 17, 2007
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    2N3643
    NPN
    Vceo(min)=30
    Hfe=100min/300max @ 150mA
    Vce(sat)<=.22 @ 150mA
    It=250MHz
    Pd=350mW
    TO-105
    Obsolete

    Replacement:
    PN3643
    Same as 2N3643, except:
    Pd=625mW
    TO-92
    Datasheet: http://www.fairchildsemi.com/ds/PN/PN3643.pdf
     
  8. Audioguru

    New Member

    Dec 20, 2007
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    The transistors on the schematic are PNP not NPN.
    Their collector current is only about 12mA so any little PNP transistors will work.

    Since the LEDs are multiplexed and are lighted for only 1/10th of the total time then they will be very dim.
     
  9. lubnaan90

    Thread Starter Active Member

    Jan 13, 2010
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    Thank you , can you plz recommend me any Specific PNP transistors i can use for the obove ,especially the ones which are easy to obtain .
     
  10. Audioguru

    New Member

    Dec 20, 2007
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    I would use 2N3906 or 2N4403 PNP transistors. If you are in Europe then you could use BC557 PNP transistors.
    I do not know where you are so I don't know what you have available.
     
  11. SgtWookie

    Expert

    Jul 17, 2007
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    Sorry about that; AudioGuru is indeed correct; they are PNP not NPN. I edited my reply about that above to change part numbers.
     
  12. lubnaan90

    Thread Starter Active Member

    Jan 13, 2010
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    It seems Sgtwookie corrected the Error , Noted the PNP transistors , Thnx .
     
  13. lubnaan90

    Thread Starter Active Member

    Jan 13, 2010
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    Thanks a Lot for also mentioning the European substitute of the above mentioned , as you see its really difficult to find "2N" & "PN" transistors here in Ukraine . Is there a European version for 2N3643 or PN3643 ?
     
  14. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    In the old days some standard transistors where called TUN (transistor universal NPN) and TUP (transistor universal PNP) by elektor.
    Here are the properties and some examples:

    [​IMG]

    [​IMG]

    [​IMG]

    They used the following connections:

    [​IMG]

    Greetings,
    Bertus
     
  15. Audioguru

    New Member

    Dec 20, 2007
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    Elektor is European so they complertely ignore North American 2Nxxxx transistors.
     
  16. lubnaan90

    Thread Starter Active Member

    Jan 13, 2010
    196
    2
    Hello every one , I could manage to find "2N 5401" PNP tansistor here , will that do ?
     
  17. SgtWookie

    Expert

    Jul 17, 2007
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    Those would work. They are really meant for high voltage, but as long as you didn't need them to sink a lot of current, they could be used.
     
  18. lubnaan90

    Thread Starter Active Member

    Jan 13, 2010
    196
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    thnx , will go ahead wth the same .
     
  19. lubnaan90

    Thread Starter Active Member

    Jan 13, 2010
    196
    2
    Hi all, tried my best to find 2N3643 & the above mentioned Replacement PN3643, unfortunately couldn't find either of them .

    can any of the below mentioned transistors be used as a replacement for the above ??

    BC 327-40 , BC 328-25 , BC 337-40 , BC 338B , BC 517 , BC 547C ,
    BC 557B , BC 557C , BC 639 , BC 807 , BC 817 , BC 847C , BC 848B,
    BC 856B , BC 857C , BC 858B

    2N 1893E , 2N 5401 , 2N 5551 , 2N 6073A , 2N 6400
     
    Last edited: Jan 20, 2010
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