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Re: power-grid physics - clocks



One satisfying way to explain this to students is to talk about the
typical consumer synchronous clock. An electric clock using 60 Hz power
as its time base is pretty accurate. There are 86400 seconds in a day.
In order for a clock to run within one second per day the daily
frequency accuracy must be within one part per 86400 or roughly 0.001%
or roughly 60.00x Hz and approaching 60.000x Hz. I believe this is the
correct ballpark. Our synchronous clock in the science building lobby,
as periodically checked against NIST, is generally better than one
second per day barring blackouts and other power glitches.

Michael D. Edmiston, Ph.D.
Professor of Chemistry and Physics
Bluffton College
Bluffton, OH 45817
(419)-358-3270
edmiston@bluffton.edu


Tom Bross wrote...

What could I tell students are the number of significant figures in the
frequency of the AC available in the lab outlets? Is is 60 Hz, 60.0 Hz,
60.00 Hz, etc.? At least what would be a reasonable estimate?