In reply to Jed Rothwell's message of Wed, 30 Mar 2011 22:09:21 -0400: Hi, [snip]
It wouldn't surprise me to find a crystal, but it wouldn't be an expensive one or temperature controlled. IOW over a period of months it would wander. The grid is more accurate, and plug in electric clocks will track accurate to less than a second over many months. A cheap crystal won't manage that as you can see with cheap watches. So if there is a crystal, then I suspect it's main purpose is to act as a backup when there is a power outage, or possibly it acts as the main oscillator, but is adjusted using the mains frequency. That would make the most sense, because then during a power outage it would still fulfill the same role without any change in circuitry, it just wouldn't get regularly adjusted. No big deal for the short period that power outages usually last. ><[email protected]> wrote: > > >> ... try alarm clocks. >> > >Try looking inside one. You will find a crystal timer. > >- Jed Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/Project.html
