+ Post New Thread
Page 1 of 2 12 LastLast
Results 1 to 20 of 27
  1. #1
    Advanced Member level 1
    Points: 4,542, Level: 15
    umery2k75's Avatar
    Join Date
    Apr 2006
    Location
    Pakistan
    Posts
    422
    Helped
    39 / 39
    Points
    4,542
    Level
    15

    how to check crystal

    I use these this kind of crystal in microcontroller project,usually 8051 with 11.0592Mhz. When my circuit is not working and I have to troubleshoot everything, I check microcontroller working with my IC programmer, it tells me whether controller is damage or fine.I don't know how can I check these crystals? I have found them faulty many times and only by replacing them, my circuit starts working fine.

    •   Alt1st January 2008, 18:31

      advertising

        
       

  2. #2
    Advanced Member level 4
    Points: 21,052, Level: 35
    E-design's Avatar
    Join Date
    Jun 2002
    Posts
    1,263
    Helped
    232 / 232
    Points
    21,052
    Level
    35

    crystal checker

    All depends what tools you have available. Using a network analyzer it is easy. Otherwise build a crystal checker.
    http://www.diy-electronic-projects.c...Crystal-Tester


    1 members found this post helpful.

  3. #3
    Advanced Member level 1
    Points: 4,542, Level: 15
    umery2k75's Avatar
    Join Date
    Apr 2006
    Location
    Pakistan
    Posts
    422
    Helped
    39 / 39
    Points
    4,542
    Level
    15

    check crystal

    I have seen the circuit, it seems good, I'll make it in a day or two.Can you define network analyzer more?



  4. #4
    Advanced Member level 4
    Points: 21,052, Level: 35
    E-design's Avatar
    Join Date
    Jun 2002
    Posts
    1,263
    Helped
    232 / 232
    Points
    21,052
    Level
    35

    crystal checker with led

    That circuit seems too complicated. I have come up with this circuit that you can make in 5min. I have tested it with crystals 2-20MHz and it works. LED will only light when there is oscillation, so it will only tell if the crystal is capable of oscillating. When there is no oscillation the voltage over the 180 Ohm resistor is too low to turn on the driver transistor. If you want to know the frequency you should use a scope or counteron node 6. Try and tell me if it works for you.

    For 1MHz crystals the capacitors should increase (say 360pF each), but then you may have problems on the 20M side. Other common transistors should work as well (2N2222, 2N3904 etc.) It won't work with 32KHz watch type crystals as the loading on the crystal gets too much. It could be modified to use a JFET at this frequency.



  5. #5
    Advanced Member level 5
    Points: 39,790, Level: 48

    Join Date
    Apr 2002
    Location
    USA
    Posts
    3,944
    Helped
    647 / 647
    Points
    39,790
    Level
    48

    crystal oscillator oscilloscope

    A network analyzer is an instrument that measures the properties (such as S-parameters and impedance) of electrical networks. It is usually a large expensive precision instrument.

    Here's a small web page showing one way to use a network analyzer to measure the properties of a crystal:
    http://www.prc68.com/I/Xec.shtml



  6. #6
    Advanced Member level 1
    Points: 5,431, Level: 17

    Join Date
    Aug 2005
    Location
    Macedonia
    Posts
    410
    Helped
    40 / 40
    Points
    5,431
    Level
    17

    check crystal in cct

    Hi Umery,
    I think the best way to check (solve) this problem is BUY NEW CRYSTALS,
    no time loss, no to many money cost,
    best regards



  7. #7
    Advanced Member level 4
    Points: 21,052, Level: 35
    E-design's Avatar
    Join Date
    Jun 2002
    Posts
    1,263
    Helped
    232 / 232
    Points
    21,052
    Level
    35

    measure 12 mhz crystal with oscilloscope

    Here is my circuit that can be used for checking watch type crystals.


    2 members found this post helpful.

  8. #8
    Advanced Member level 1
    Points: 4,542, Level: 15
    umery2k75's Avatar
    Join Date
    Apr 2006
    Location
    Pakistan
    Posts
    422
    Helped
    39 / 39
    Points
    4,542
    Level
    15

    how to check a crystal if it oscillates

    @pasicr
    Yes, this is what I had done today, bought dozens of crystals today :D

    These circuits tells whether there's an oscillation or not, but I think if it has feature of telling the exact frequency, it would be very good, that is if a crystal is rated at 12Mhz, if I check this crystal and it give me the reading as 11.99Mhz so I can say it's 99% accurate.I mean can we check it in the same way as we check the resistances,capacitance and inductance by multi meters.



    •   Alt2nd January 2008, 09:25

      advertising

        
       

  9. #9
    Member level 4
    Points: 1,708, Level: 9

    Join Date
    Jul 2007
    Location
    Belgium
    Posts
    73
    Helped
    18 / 18
    Points
    1,708
    Level
    9

    to check a crystal

    Quote Originally Posted by umery2k75
    @pasicr
    ...that is if a crystal is rated at 12Mhz, if I check this crystal and it give me the reading as 11.99Mhz so I can say it's 99% accurate....
    Strange mathematics :(
    99% of 12MHz is 11.88MHz :)

    Why not using a standard digital scope?
    Problem is, what accuracy do you expect?
    Any particular reason why you don't trust the manufacturer?



    •   Alt2nd January 2008, 11:14

      advertising

        
       

  10. #10
    Advanced Member level 1
    Points: 4,542, Level: 15
    umery2k75's Avatar
    Join Date
    Apr 2006
    Location
    Pakistan
    Posts
    422
    Helped
    39 / 39
    Points
    4,542
    Level
    15

    diy crystal tester

    Oh I didn't do the mathematics I just wrote the rough figure for the 99%,
    well I have digital oscilloscope from Tektronics, I didn't know if I could use this to measure the quartz crystal.I do trust manufactures.
    I don't want to have high accuracy, error of 1-5% is fine to my work.I was just wondering



  11. #11
    Full Member level 4
    Points: 3,663, Level: 14

    Join Date
    May 2004
    Location
    Singapore
    Posts
    224
    Helped
    4 / 4
    Points
    3,663
    Level
    14

    crystal oscilloscope

    Quote Originally Posted by umery2k75
    I use these this kind of crystal in microcontroller project,usually 8051 with 11.0592Mhz. When my circuit is not working and I have to troubleshoot everything, I check microcontroller working with my IC programmer, it tells me whether controller is damage or fine.I don't know how can I check these crystals? I have found them faulty many times and only by replacing them, my circuit starts working fine.
    Do you know how to use oscilloscope? Just put the probe to the crystal pin. You should see 11.xxxMhz digital signal. Very simple to do that.

    Second, please check the peak-to-peak signal to make sure the peak voltage is correct.

    In short:

    (1) frequency
    (2) Peak-to-peak signal

    Why wondering? I have used this method many times to check the crystal.



  12. #12
    Advanced Member level 4
    Points: 21,052, Level: 35
    E-design's Avatar
    Join Date
    Jun 2002
    Posts
    1,263
    Helped
    232 / 232
    Points
    21,052
    Level
    35

    mhz cristal tester schematics

    Caution: The loading from a 10X scope probe will often be enough to stop the oscillator, especially where it uses a low frequency crystal with high internal resistance.



  13. #13
    Advanced Member level 1
    Points: 4,542, Level: 15
    umery2k75's Avatar
    Join Date
    Apr 2006
    Location
    Pakistan
    Posts
    422
    Helped
    39 / 39
    Points
    4,542
    Level
    15

    how to check crystal in microcontroller

    I have used the oscilloscope many times, but I didn't know that it could measure the crystal frequency when not powered, as you have mentioned earlier that I must connect the probe to the crystal pin and check the desired parameters and probes contains some resistance,capacitance and inductance, as to make them possible to switch from X1 to X10 and they are passive in nature.So what makes the crystal excites to the 11.XXX Mhz.There must be some sort of voltage difference between the two probes to excite the crystal to produce the frequency, so how could probe do that.Does this mean a pair of probe has some potential difference across them?
    Right now I'm making a project board for PIC16F877A and I'm busy in soldering the circuits from two days back.My work is almost complete now.I'll perform this experiment of your very soon and I'll post my findings.:D



  14. #14
    Advanced Member level 5
    Points: 39,790, Level: 48

    Join Date
    Apr 2002
    Location
    USA
    Posts
    3,944
    Helped
    647 / 647
    Points
    39,790
    Level
    48

    how to check crystal if working

    I'm sure feiutm9898 meant that the oscillator must be powered-up and running before you can measure it with an oscilloscope.

    A crystal oscillator's frequency can be varied slightly by adjusting components in the oscillator circuit. Some circuits provide a small trimmer capacitor so you can easily fine-adjust the frequency to the desired value.

    As E-design suggested, poking a scope probe into an oscillator's analog circuit could stop it. Even if it doesn't stop, the probe's capacitance will surely change the frequency. Try measuring the frequency at the oscillator's output, or somewhere down the counter chain. Sometimes you can hold the probe tip close to the oscillator without actually touching it, and still measure the frequency -- that won't disturb the frequency very much.

    Most scopes aren't very accurate for measuring crystal oscillator frequency. A frequency counter would be much better, but again don't poke the counter's probe directly into the oscillator's sensitive analog circuit.

    A crystal is somewhat fragile. When soldering, don't overheat it. Probably a good idea not to drop it either.

    For a very crude check of crystal operation, you could simply connect the crystal between a sinewave generator and your oscilloscope. At the crystal's series resonance frequency, the signal should come through pretty strong. Tune carefully because the bandwidth will be very narrow, maybe a few kHz for an 11 MHz crystal.



  15. #15
    Member level 3
    Points: 1,493, Level: 8

    Join Date
    Feb 2007
    Posts
    60
    Helped
    3 / 3
    Points
    1,493
    Level
    8

    how to check crystal

    you can't be shure if the Xtal its ok using a scope.

    the scope has an impedance that perturbes the signal.

    i recommend u to use any of circuits above.



  16. #16
    Advanced Member level 1
    Points: 4,542, Level: 15
    umery2k75's Avatar
    Join Date
    Apr 2006
    Location
    Pakistan
    Posts
    422
    Helped
    39 / 39
    Points
    4,542
    Level
    15

    probing 12mhz crystal

    feiutm9898 told me that oscilloscope can check the crystal.Yes, he was correct.I got successful to measure the clock frequency accurately upto 4 significant figures after decimal i.e 11.xxxx

    As far as the oscilloscope probes are concerned, they are of high impedance they don't disturb the circuit and neither impose any external effect.

    Oscilloscope is a better option, because it can show:
    1)Crystal is working(Above circuits can also tell)
    2)At what frequency is it working(Above circuits can't tell you, oscilloscope can tell you)


    I have demonstrate you using oscilloscope to measure crystal exact frequency.



    2 members found this post helpful.

  17. #17
    Full Member level 6
    Points: 4,359, Level: 15

    Join Date
    Nov 2004
    Location
    Romania
    Posts
    379
    Helped
    42 / 42
    Points
    4,359
    Level
    15

    crystal checker circuits

    Generally you need to test only if it oscillates.
    The frequency error it's under ±5kHz for crystals in the 1-25MHz range, and if high precision is needed you can compensate in software. The frequency may have an offset from the standard value, but it's highly stable.
    To get a small error use high value loading capacitors or trimmers. The disadvantage of high capacitance it's higher current consumption of the uC.



  18. #18
    Newbie level 3
    Points: 468, Level: 4

    Join Date
    May 2010
    Location
    India
    Posts
    4
    Helped
    0 / 0
    Points
    468
    Level
    4

    Re: Check crystal working?

    I only want to check weather it Ocilates or not?,

    what is the simple way to check that?



  19. #19
    Super Moderator
    Points: 41,040, Level: 49
    Fragrance's Avatar
    Join Date
    Jul 2002
    Location
    East Of Earth
    Posts
    1,169
    Helped
    207 / 207
    Points
    41,040
    Level
    49

    Re: Check crystal working?

    HI

    Simple and best method is if you have frequency counter simply check frequency on osc out pin of controller, you will get same same frequency crystal on that pin which show crystal working fine

    regards
    Fragrance



  20. #20
    Newbie level 4
    Points: 452, Level: 4

    Join Date
    Jul 2010
    Location
    banglore
    Posts
    6
    Helped
    0 / 0
    Points
    452
    Level
    4

    Re: Check crystal working?

    hey,i wanna check crystal 0f 8.704Mhz,using network analyzer,plz help me,i wanna know more abt the test procedure



+ Post New Thread
Please login
Page 1 of 2 12 LastLast