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Re: Alternating Current

I just did a lab today with my Pre Calculus class. Since we have
introduced sinusoidal variation I had them use a CBL to look at the
light intensity from an incandescent bulb sampling every .0001 seconds
for 100 data points.
(cuts)
full cycle of light intensity. The frequency came out consistently at
124Hz by the way and I wonder if the power company is typically this far
off their standard value of 2*60Hz?

David,

NO WAY on the 124 Hz. The power company is VERY fussy about delivering as
exactly 60.000 Hz as it can be within reason. Fifteen years ago I heard a
statement that the power engineers would control generator speeds such that
there were exactly the right number of cycles each and every day, because so
many critical devices (clocks, synchronous motors etc) that would be
incorrected or even damaged if things got out of hand. I wish they
could be so good with the actual voltage levels (like easily 90-135VAC
here in Flag) -- they most own stock in the surge supressor companies or
something :^).

I think you're seeing something else, perhaps a more subtle problem with
the CBL timebase.

Dan M



Dan MacIsaac, Assistant Professor of Physics and Astronomy, Northern AZ Univ
danmac@nau.edu http://purcell.phy.nau.edu PHYS-L list owner