[time-nuts] Quiet clocks, noisy clocks
Ron Bean
time at rbean.users.panix.com
Sat Jan 5 19:29:06 UTC 2019
A recent thread talked about noisy clocks (1 tick per second). Some of
you may have noticed that it's now possible to buy cheap quartz clock
movements that have a continuous-sweep second hand, and don't tick once
per second. For example, klockit.com sells two different brands (Seiko
and Quartex, the latter is owned by the same company that owns klockit).
AFAIK LaCrosse is the only company making consumer-level quartz clocks
with this feature, and only on certain models. I've found that the
plastic gears do make some noise, especially with a large clock face
that acts as a resonator, and they may be audible in a quiet room. But
IMHO they're less bothersome than 1 tick per second.
A few years ago I put a 'scope on one of the Quartex movements (pic
attached, same pic at http://www.panix.com/~rbean/clock/clock-01.jpg )
Like other quartz clocks, they use a "Lavet" type stepper motor
https://en.wikipedia.org/wiki/Lavet-type_stepping_motor
But the electronic timing and mechanical gearing are different (16 pulses
per second). The amplitude is equal to the battery voltage (I think I used
a lithium primary cell, which is a slightly higher voltage than alkaline).
Some time ago, someone on this list mentioned that he knew someone who
worked with the controller chips in cheap clocks and watches. If anyone
knows which chip runs these things, I'd love to see a data sheet. They
seem to keep remarkably good time for something that costs so little.
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