[time-nuts] Is a crystal likely to change frequency by 3% ?
alexpcs at ieee.org
Sat Sep 13 08:44:18 EDT 2014
there is only one magnet, which drives the fastest moving arm -- the
pointer for the seconds -- the other arms are connected via gears, by
the way that case with the weak periodically recovering battery is an
observed one, I connected a paper chart recorder to the clock and
recorded the battery voltage change and the driver pulses of the magnet
-- the recorder was not able to follow the individual pulses, but the
On 9/13/2014 5:08 AM, Dr. David Kirkby (Kirkby Microwave Ltd) wrote:
> On 13 Sep 2014 01:23, "Alexander Pummer" <alexpcs at ieee.org> wrote:
>> just open the box, look for the wires which going to the magnet which
> drives the minute hand and measure the period time -- not the frequency, it
> is to low
>> yes analog quarz clock slows down as the battery get old, you will be
> surprised, that the driver pulse's period time dos not change, but
> sometimes the divider chain or the mechanic skips a pulse, as the battery
> voltage drops further suddenly the clock mechanic or the electronic will
> stop working, takes less current so the battery recovers a bit, because the
> magnet did not used power for a while, and will run again for a while, the
> pause between two run time will be larger and larger so the clock looks
> like going slower
> So if it the mechanics skips a pulse, one really needs some method of
> measuring the position of the hands and recording that.
> In any case, the explanation you give is different to Dave McGuire.
> Maybe the second hand is more likely to slip if trying to fight gravity
> (between 30 and 0 seconds) and less likely when gravity helps (between 0
> and 30 seconds)
> It would be interesting to see a detailed study of this.
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