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re: Non-Linear Coil Winding Experiment.





---------- Forwarded message ----------
Date: Sat, 18 Oct 1997 17:13:32 -0600
From: terryf-at-verinet-dot-com
To: Tesla List <tesla-at-pupman-dot-com>
Subject: re: Non-Linear Coil Winding Experiment.


>Hello All,
>        I agree that the resonant frequency of a loaded tuned circuit is in
>fact sqrt(1/LC-(R/2L)**2).  The fact that resonant frequency is changing
>substantially is probably explained by a combination of both changing
>effective series resistance and distributed capacitance.
>>>SNIP...<<<
>Mark S. Rzeszotarski, Ph.D.
>
>

        After using pencil, paper, and the work of a 248 year old
mathematician named Laplace, I have found that Fo does indeed work out to
sqrt(1/LC-(R/2L)**2) (rad/sec) when applied to the standard model of a Tesla
coil. I learned something today  *:-)

        Since I used a 50 ohm generator, this would have introduced an error
of ~0.1% to the original numbers which won't change anything I measured
substantially.  

>      The second component of distributed capacitance is the external
>capacitance which is due to the fact that the mean potential between each
>turn and earth represents an isotropic capacitance.  This effect is present
>if one end of the coil is grounded to earth, which is, of course, the way we
>normally operate Tesla coils.

I made pictures of the field maps around my three coils.  I'll try to get
them up on my web page this weekend.  They show how the fields varied around
the three coils.  There is a way to estimate the relative capacitance from
these maps but I'll have to dig through my fields book to remember how a 166
year old physicist named Maxwell did it.


        For all who ask, the pictures and description of the computer
controlled coil winder can be seen at:

http://www.verinet-dot-com/~terryf/Tesla/Projects/CoilWind/Winder.html 

Note: upper and lower case letters. It still could use polish and additions
but it's finally up. If you have any problems please E-mail me instead of
this group.  This will save Chip from a bunch of "I couldn't find it"
messages if I slipped up. :-)

        Terry

        terryf-at-verinet-dot-com