Chronology Current Month Current Thread Current Date
[Year List] [Month List (current year)] [Date Index] [Thread Index] [Thread Prev] [Thread Next] [Date Prev] [Date Next]

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.

When one does this, the calculator shows a beautiful sinusoidal graph
and the regression analysis shows an excellent fit with supporting
residuals.

However, I would have expected to see a graph more like |sint| which
should not look like a sin but should have the frequency of double the
line voltage frequency since each half of the voltage cycle produces a
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?

Can anyone help me with this? Am I really seeing |sint| and it just
looks like sint? Has anyone else tried this?

Thanks for the help.
--
David Abineri dabineri@choice.net