[time-nuts] Quiet clocks, noisy clocks

[Ron Bean]

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.

-------------- next part --------------
A non-text attachment was scrubbed...
Name: clock-01.jpg
Type: image/jpeg
Size: 23285 bytes
Desc: not available
URL: <http://febo.com/pipermail/time-nuts_lists.febo.com/attachments/20190105/29e457fa/attachment.jpg>