Crystal Oscillator As Timebase?

Discussion in 'General Electronics Chat' started by Adrastos, Feb 26, 2009.

  1. Adrastos

    Thread Starter Member

    Jan 5, 2009
    17
    0
    Hello,

    I need a 1 Hz timebase for several projects I want to do, running off DC battery power (no 60 Hz mains power to derive from). I've come across the attached circuit, from: http://ourworld.compuserve.com/homepages/Bill_Bowden/page11.htm#oscilate.gif. (I plan to use the circuit on the right in the picture), to develop a 32.768 kHz timebase which I'll divide down by 2^15, to a theoretical 1 Hz timebase with which to trigger clock pulses in a series of counters. Only problem I'm having, is the variable capacitor. I'm assuming this is to adjust the oscillator to the exact frequency, but it doesn't say anything about the range this variable trimmer should be.

    So, can anyone help me with that range? Or perhaps a better / easier means of getting a 1 Hz timebase?

    Thanks very much!
     
  2. Wendy

    Moderator

    Mar 24, 2008
    20,766
    2,536
    Look up the CD4060 datasheet, it will generate a 2Hz time base with the same crystal.
     
  3. Adrastos

    Thread Starter Member

    Jan 5, 2009
    17
    0
    Thanks kindly!
     
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