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From: gnome@oliveb.UUCP (Gary)
Newsgroups: sci.electronics,misc.consumers
Subject: Re: info on clocks using battery backups
Message-ID: <1436@oliveb.UUCP>
Date: Wed, 17-Jun-87 14:22:52 EDT
Article-I.D.: oliveb.1436
Posted: Wed Jun 17 14:22:52 1987
Date-Received: Sun, 21-Jun-87 10:16:49 EDT
References: <3622@cisunx.UUCP>
Organization: Olivetti ATC; Cupertino, Ca
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Xref: mnetor sci.electronics:830 misc.consumers:2059

in article <3622@cisunx.UUCP>, nf165636@cisunx.UUCP (meyers     m) says:
> How do the clocks (and clock radios) that run on main power (110/60 Hz)
> count the time ? Especially those that use battery backups. In this case
> do they use a quartz crystal ? Does that mean that these can be used
> on 110/50 Hz or any other frequency ? Any info will be appreciated.

AC driven clocks generally get their clock timing from dividing-down
the 60Hz to the 1Hz seconds-clock.  Some clocks have a little circuit
that allows the clock to ride-out short power failures.  Often it is
a cheap, low accuracy oscillator that "locks" to the 60Hz (when available)
and self oscillates at about 60Hz when the line power is gone.

Most crystal driven clocks are battery-only.  Note, I said most.
So, in general, if it plugs into the wall, it won't work too well
in other countries with 50 hz.  (Some have a switch for 50/60Hz, though).

Gary