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[Phys-L] Foucault pendulum



Mike is right:
- - - - -
I'm guessing the "feedback" John Sohl was talking about is unintentio=
nal
feedback as opposed to designed feedback. If that is not true, ignor=
e
the rest of this message.
- - - - *
I tried a diode but that didn't help. Because it is so cramped in the=
attic I couldn't do lots of experimenting. (But I've got the electro=
magnet in my hands now.) I didn't think to use varistors or zeners. T=
he back emf is not blowing out the circuit but I think it is feeding =
signals in that I don't want. (That's why I tried the diodes.) I'll b=
e able to put a scope on it now and see more about what's happening.=
=20
=20
Brian's suggestion of a simple AC circuit is interesting but I wonder=
about phase issues and keeping the pulse period exactly the same as =
the pendulum's period. I'll look up the articles in Sci. Am.=20
=20
Still open to circuit ideas.
=20
Thanks.
=20
John
=20
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
John E. Sohl, Ph.D.
Professor of Physics
Weber State University
2508 University Circle
Ogden, UT 84408-2508

voice: (801) 626-7907, fax: (801) 626-7445=20
e-mail: jsohl@weber.edu
web: http://physics.weber.edu/sohl/
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