[time-nuts] Quartz assisted pendulum clock.
Dr. David Kirkby
david.kirkby at onetel.net
Thu Jan 5 10:25:33 EST 2006
Dennis O'Keefe wrote:
> Earlier this week I made a claim that I am a Time Nut from way back. In
> further evidence of that, I report that I actually clipped and saved that
> Reference: Scientific American, September 1974, pages 192 - 198, in a section
> called The Amateur Scientist.
> The man made a quarts crystal oscillator that sent a pulse to an electromagnet
> that was placed near a permanent magnet mounted on the pendulum of a wall (not
> a grandfather) clock. The pendulum was set a bit slow for its 72 per minuet
> beat and the electronics gave it a push each cycle to make it swing at the
> correct rate.
> He had faster and slower count settings to adjust its rate. The ultimate check
> was still listening to WWV while looking at the clock.
If you have an electronic copy of that I'd like to see it. I found a
text-only version, but would like to see the original.
I believe he used a TCXO. I have a small French clock that sits on a
mantelpiece, I'd like to do that too, but getting power to it is not too
easy. My wife is not keen on wires going to it.
I did think about solar power, or powering it from the pendulum itself,
but neither look too practical in my particular circumstances.
I did wonder if its possible to put the electromagnet under the clock,
rather than inside it, but that will probably put too much wear on the
You can probably cut down the power consumption by running the clock at
as accurate as possible (not slow) and using a bipolar pulse, rather
than a uni-polar one.
Certainly an interesting idea.
BTW, if you look at the sound produced by an old clock wth a microphone
and scope, it is far from regular. I suspect the pendulum is more so
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