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Wire length,resonance, and Q (fwd)


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From:  Mark S Graalman [SMTP:wb8jkr-at-juno-dot-com]
Sent:  Wednesday, May 27, 1998 4:23 AM
To:  tesla-at-pupman-dot-com
Subject:  Re: Wire length,resonance, and Q (fwd)

  I have to wonder here if there isn't a simple
misunderstanding of 1/4 wave resonance, the fact
that we are talking about an ELECTRICAL 1/4 wave
and not a PHYSICAL 1/4 wave. That a 'monopole'
tesla secondary is a ELECTRICAL 1/4 wave from
the bottom to the top, and any situation where one
has a current node at one end and a voltage node
at the other is being operated as a 1/4 wave electrically
regardless of its physical length. If one installs a
large enough terminal "C" on the coil actual
physical and electrical 1/4 wave resonance can be
obtained and I run my coil in that mode, but I see no
REAL advantage other than I think at that point a
majority portion of the secondary energy is stored in the
terminal "C" in comparison to the coils self capacitance.

Mark Graalman

On Tue, 26 May 1998 23:14:23 -0500 Tesla List <tesla-at-pupman-dot-com> writes:
>
>----------
>From:  Malcolm Watts [SMTP:MALCOLM-at-directorate.wnp.ac.nz]
>Sent:  Monday, May 25, 1998 11:28 PM
>To:  Tesla List
>Subject:  Re: Wire length,resonance, and Q (fwd)
>
>Hi Bart,
>
>> From:  Barton B. Anderson [SMTP:mopar-at-uswest-dot-net]
>> Sent:  Saturday, May 23, 1998 11:40 PM
>> To:  Tesla List
>> Subject:  Re: Wire length,resonance, and Q (fwd)
>> 
>> Hi Malcolm (btw - thanks for the great replys! - love this stuff!),
> 
><snip>
>> Your probably correct here as the Medhurst's formula considers 
>geometric dimensions
>> where the standard 1/4 wave formula does not. This particular 
>consideration adds
>> substance that only tested methods can provide.
>> 
>> Medhurst formula: C = K * D
>> C = solenoid self-capacitance in picofarads.
>> K = a constant which depends on the ratio of the coil height and 
>diameter.
>> D = diameter of solenoid in centimeters.
>> 
>> This formula takes into consideration the geometric ratio and 
>corresponds it to a given
>> K. How K was actually determined I assume is by way of emperical 
>data. However, for the
>> secondary to yield it's highest voltage potential at the toroid 
>(regardless of top C),
>> there must be a 1/4 wave *situation* occurring in the circuit, even 
>if it is not based
>> entirely on the 1/4 wave wire length *situation*. I guess what I'm 
>contemplating is if
>> the 1/4 wave length of the P-freq. would correspond to the length of 
>the secondary
>> winding if the unknown variables were taken into account with the 
>formula? I wish I
>> knew just what all those variables were. Would't Vout be optimized?
>> 
>> Bart
>
>Don't see why. If yu feed in a lump of energy and that energy is 
>mostly concentrated in Ctop at some stage then the old 0.5CV^2 
>applies.  I loved Greg Leyh's explanation of why it *should* apply, 
>namely that the V^2 term is highest at the top. I think calculating 
>Vout based on no terminal is academic unless one runs with no Ctop 
>but then how well can you do if you are lacking ROC at the top?
>What thinks anyone?
>
>Malcolm
>
>
>

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