[time-nuts] How to get 32.768KHz from 10MHz.
James.P.Lux at jpl.nasa.gov
Mon Jul 28 20:19:32 EDT 2008
At 05:04 PM 7/28/2008, you wrote:
>Quartz analogue clocks almost universally use a bipolar motor, a two
>magnetic circuit with the minimum reluctance axis displaced from the
>of the energised field.
>When activated the 2 pole magnetic rotor aligns with the magnetic
>field, when the field collapses,
>the magnetic rotor moves a little towards the position of greater
>self attraction, so that it is
>set up for a move in the right direction when the reverse field is
>To drive these motors as clock displays you either replicate the
>alternate 1.5 volt 20mS pulses, or connect a capacitor,
>about 10 - 100 mfd in series and drive them with a 0.5 hertz square
>wave of about 1.5 volt amplitude.
>The drive voltage and pulse duration should be adjusted for each type
>of motor, or else
>the voltage and capacitor size so that reliable stepping occurs.
>Overdrive can stop some types as the rotor "poles".
>just in case you were interested,
>cheers, Neville Michie
The ones I have here have a single solenoid with a sort of wishbone
shaped thing around it. A curved metal rod with a thicker center
portion is connected between the arms of the wishbone. The rod goes
through the center of the solenoid, and it looks like when the
current pulse is applied to the solenoid, the armature is pulled through.
Imagine a sort of pendulum with the solenoid at the bottom.
In any case, faking the 32.768 is going to be easiest, because the
clock mfr has already fooled with figuring out the right voltages,
currents, and pulse widths.
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