Re: the cure for racing sparks

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi,

Here is a frequency sweep of my small coil in normal firing configuration:

http://hot-streamer-dot-com/temp/2001-03/Tek00000.gif

Aslo a movie at:

http://hot-streamer-dot-com/temp/Animation4.gif

Just a "cheap scope trick" but I thought it illustrated the "double-hump"
thing nicely.  The coupling is only 0.117.

http://hot-streamer-dot-com/TeslaCoils/MyCoils/SmallCoil/SmallCoil.htm

Cheers,

	Terry

At 06:31 PM 7/11/2002 +0100, you wrote:
>D.C. Cox wrote:
>
>> A second note is that you may be "overcoupled" which causes the
>> "double-hump" on the freq, ie, splitting the res. freq. into two
>> different freqs which beat against each other. 
>
>This is another myth, which seems to have been quite popular
>during the early 90's.  The idea that mode splitting occurs when
>the coupling reaches a certain level is false, and the presence
>of the double hump in the frequency response doesn't imply
>overcoupling.
>
>The quarter wave resonance of the secondary is 'split' into two
>separate resonances by the introduction of a tuned primary, and
>this occurs no matter how small the coupling.  The two frequencies
>are Fres/sqrt(1+k) and Fres/sqrt(1-k) for high Q coils where Fres
>is the resonant frequency of the uncoupled coils.  At normal TC
>coupling coefficients, the mode frequencies are offset around 10%
>each side of Fres, and as k is reduced to zero the two mode
>frequencies converge smoothly to Fres.  
>
snip..........