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Secondary frequency: I got it (fwd)
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From: RWB355-at-aol-dot-com [SMTP:RWB355-at-aol-dot-com]
Sent: Wednesday, August 19, 1998 10:58 AM
To: fwd
Subject: Secondary frequency: I got it (fwd)
Hi to all,
I want to thank all for you for your help.Okay, so I got shot down in flames,
guys.
He (BTW "He" is Mike Hammer) was RIGHT and I was WRONG!!
I used (as some of you assumed correctly) the 1/4 wave theory. After thinking
about this I now can understand why a Tesla (secondary) is not just a piece
of wire (as in "antenna") but rather a "lumped system". So 1/4 wave theory
wonīt work. I (ahem, cough, cough) do have an excuse though. I built my last
Tesla 15 years ago (I was 14) and at the time 1/4 wave was still the "hit."
You never stop learning!!
After digging some of the new math (Medhurst & Wheeler) I can understand now
that different diameters DO change capacitance and inductance and one cannot
use the wire length alone.
The reason I placed the question, was because I am presently writing a new TC
prog and if I take the time, why not do it right ?!
After sifting through everbodyīs results and programming the new stuff I found
Bart Andersons calcs where closest to mine (using the new math). The coils
were unloaded (no top cap), so perhaps this is why some of you got different
results then Bart and I did. Perhaps it is also because I didnīt take "K" for
the Medhurst formula from a table, but rather calculated the value. This
should be a little more exact.
My "NEW" calcs turned out:
Coil A: 6": (783 turns) (40.75mH) (7.44pf) FRes=289.2Khz
Coil B: 3": (1571.5 turns) (24.71mH) (8.2pf) FRes=356.3Khz
Now I do have a last question: Does anyone out there have a formula with which
one could calc the aprox. spark length. I know itīs difficult and I just want
to give the coiler using my prog an estimation of the spark length possible.
Iīve heard of the theory 500W are aprox 12" sparks. I donīt think this is all
to accurate as I have buit tcīs with more input and less sparks and less input
and more sparks. One should be able to calc the spark length using the
capacitance and inductance of the secondary (given input power) though. Any
ideas ?
Thanks,
Safe and happy coiling to all,
Reinhard