crystal not oscillating

Discussion in 'General Electronics Chat' started by wongchoy88, Dec 9, 2014.

  1. wongchoy88

    Thread Starter New Member

    Sep 10, 2014
    4
    0
    hi guys,
    i used a SMD type 32.768Khz crystal for my project with two 10pF to GND, its not functioning. but once i change the crystal to TH type crystal, it work. May i know what is happening? (note: i only change crystal but remain same connection and capacitance.)
    upload_2014-12-9_15-48-55.png
     
  2. alfacliff

    Well-Known Member

    Dec 13, 2013
    2,449
    429
    a crystal will not oscilate by itsself, it needs a transistor or other amplifying device to oscilate. it can act as a narrow bandwidth filter, tho.
     
  3. takao21203

    AAC Fanatic!

    Apr 28, 2012
    3,648
    477
    you could try leave out the caps or only use 5pf for the SMD part
     
  4. wongchoy88

    Thread Starter New Member

    Sep 10, 2014
    4
    0
    Thanks for your suggestion
    i tried
    but its also not working.
    i tried 27pF as well but also not working.
     
  5. bertus

    Administrator

    Apr 5, 2008
    17,137
    3,009
    Hello,

    To what is this circuit connected?
    You have the labels XTAL_IN_32KHZ_SW and XTAL_OUT_32KHZ_SW in your schematic.

    Bertus
     
  6. wongchoy88

    Thread Starter New Member

    Sep 10, 2014
    4
    0
    hi,
    i connected to a DIP switch to make option between crystal and clock generator. Because the crystal not functioning, so i force to use a clock chip provide frequency. but i want find out the problem, in case i face the same problem again.
     
  7. bertus

    Administrator

    Apr 5, 2008
    17,137
    3,009
    Hello,

    What chip are you using?
    Did you "tell" the chip to use the internal or external oscillator?

    Bertus
     
  8. atferrari

    AAC Fanatic!

    Jan 6, 2004
    2,838
    941
    Where do you use that? In a micro?

    May I know in turn, what that change is? The settings in some IDE to program a micro?

    Do not asume that people knows what you are talking about. Try again.
     
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