In article ,
Meat Plow wrote:

On Wed, 19 Aug 2009 18:14:14 +0100, "Dave Plowman (News)"
wrote:

In article ,
Jeff Liebermann wrote:
Yup, but the long-term average will be pretty good -- gain a little in
the daytime, lose a bit at night (or the other way around; could be
either one depending on how the circuit was set up).

Maybe, if the wearer maintains a regular schedule. That's a fair
assumption, until the wearer changes their usage pattern, such as
going on a ski trip.

Also, please note that the original discussion was over the accuracy
of a computah clock, not a wrist watch. Unless left on continuously,
computers don't maintain a set schedule. Even so, their internal
temperature is affected by the building environment.

But is there any real difference between a 'quartz' watch and a PC clock?
They both rely on a low cost crystal?

Size?
Temp?

Does a tiny watch xtal garner any more accuracy merely because of its
size?

Because of the oscillatory mode, low-frequency watch crystals are
notoriously inaccurate.

Does a watch xtal have a different temperature coefficient?

Yes; poor, for the same reason.

Isaac