crystal oscillator

Discussion in 'General Electronics Chat' started by kppp, Apr 23, 2008.

  1. kppp

    Thread Starter Member

    Apr 23, 2008
    14
    0
    hello to all;
    can u tell me how to check the rtc and crystal oscillator functioning?
    thank u
    :)
     
  2. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Well, what's the frequency of your realtime clock crystal?

    Or, what's the part number of the IC that's being used as a driver/divider?

    It's easiest to use an oscilloscope or logic probe to check the output of the RTC. For the crystal itself, you may need to remove it from the RTC circuit and make a test circuit for it. What kind of test circuit depends upon the frequency of the crystal. If you drive crystals too hard, you can cause them to shatter. If you drop them, they will also shatter.
     
  3. gotumal

    Active Member

    Mar 24, 2008
    99
    0
    Hi,

    The crystal for RTC is always of 32.768KHz. You need to check with the CRO. Also please ensure that the load capacitance is OK. If you are driving from other clock sourse you should use a series resistance.
     
  4. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    It's not always 32.768kHz. RTC's implemented using a CD4045B use a 2.097152MHz crystal (with obligitory caps in the 10s of pF range)
     
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