[time-nuts] How to get 32.768KHz from 10MHz.

Chuck Harris cfharris at erols.com
Thu Sep 4 16:33:28 EDT 2008


Hi Brooke,

The drive for the coils is really not very critical.  All you need is
a cmos inverter and a couple of capacitors:

~1PPS--[>o---+----[>o-------|(-----+
~            |                     |
~            |                   MOTOR
~            |                     |
~            +--------------|(-----+
~

Yes, it is just that easy.

-Chuck Harris


Brooke Clarke wrote:
> Hi John:
> 
> All the quartz clocks I've taken apart have a single coil, for example see:
> http://www.prc68.com/I/QuartzClk.shtml
> 
> The drive to that coil is bi-polar and is from a single AA cell, so the driver 
> IC must use an H-bridge.  If you want to drive a clock like this at 1 PPS from 
> a 10 MHz source you will need to use some kind of conversion circuit.  That's 
> why it's easier to generate the 32768 Hz signal and just drive the xtal pins on 
> the  clock's IC.
> 
> Have Fun,
> 
> Brooke Clarke



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