How to check a crystal

Discussion in 'General Electronics Chat' started by nerdegutta, Feb 27, 2010.

  1. nerdegutta

    Thread Starter Moderator

    Dec 15, 2009
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    Hi,

    I have a bunch of crystals, with 2 pins and 4 pins.

    I have a frequency counter, and I can test the 4 pins, but how can I easily test the 2 pins?

    Maybe I need a little circuit?
     
  2. bertus

    Administrator

    Apr 5, 2008
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  3. nerdegutta

    Thread Starter Moderator

    Dec 15, 2009
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    Thanks.

    Guess I can use a BC549c, instead of the BC550c?

    I compared their datasheets, and to me they seem to be pretty like.
     
  4. t06afre

    AAC Fanatic!

    May 11, 2009
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    The BC550 and 549 are compatible. The BC550 can be at higher voltages than the BC549. But at 9 volt this does not matter at all
     
  5. nerdegutta

    Thread Starter Moderator

    Dec 15, 2009
    2,515
    785
    Thanks. I will try to build it now.

    :)
     
  6. nerdegutta

    Thread Starter Moderator

    Dec 15, 2009
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  7. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    Strange that you could not get the x-tal tester to work.
    The schematic you posted is basicaly the same.

    Bertus
     
  8. nerdegutta

    Thread Starter Moderator

    Dec 15, 2009
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    Yes, I noticed that too.

    On the last circuit, I changed the BC549 to 2N2222. Maybe thats why?
     
  9. bertus

    Administrator

    Apr 5, 2008
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    Hello,

    That could be.
    The BC549 is an audio transistor.
    The 2N2222 is a switching transistor, that might be more of use for the circuit.

    Greetings,
    Bertus
     
  10. Wendy

    Moderator

    Mar 24, 2008
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    Uhh, guys, protoboards and crystals do not get along. You are loading a sensitive circuit down with a heck of a capacitance.
     
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