[time-nuts] Sidereal timekeeping

Neville Michie namichie at gmail.com
Thu May 19 05:23:13 UTC 2011


Analog quartz clocks may be used as slave clocks.
You do not even have to disconnect the quartz movement.
Just find the coil on the motor and drive it with a square-wave of  
0.5 hertz,
in series with a capacitor (about 50mfd) and a resistor (about 200 ohms)
Each type of clock is different, though they all are driven by  
something like 1.5 V
20ms alternate polarity pulses.
The actual values are not critical but must be determined for each  
type of clock.
If the capacitor resistor combination is wrong it will not work. Too  
much signal
will make motors "pole" and refuse to rotate. The capacitor charges  
when the
polarity changes and that current operates the clock. The resistor  
sets the length
of the pulse together with the capacitor value, as well as setting  
the maximum current.
Just swap values until the action is quiet, definite and reliable.
I have used this method on at least 4 different types of quartz  
clock, usually from a 5 volt
logic signal.
Cheers,
Neville Michie



More information about the time-nuts mailing list