From: "Malcolm Watts"
Date: Thu, 23 Nov 2000 09:15:30 +1300
Subject: Re: [TSSP] E-Tesla6.11
Hi Terry,
I once heard a description of the top end of the coil as
being a piece of wire flapping in the breeze. I have no doubt at all
that the inductance of those turns is effectively not there in an
unterminated coil because of the current profile. The wire is still a
conductor however. This leads to a number of very interesting points
I would like to put out there for comment.
#1 - It is known that placing a cut in a terminal plonked hard on top
of the windings affects resonant frequency to only a small degree
given what k must be like between the terminal and those top turns. I
have wondered what the coupling profile must be like (this has direct
relevance to primary coupling as well). Suppose a terminal negates
some of the inductance one would think it adds to the top of the coil
by altering the current profile. Then putting a cut in it such that
it is no longer a shorted turn must alter that effect but it cannot
change the capacitance to any significant degree. Any comments on
that one?
#2 - is your calculated Cself the Medhurst value or the DC value?
Given R. Jones scenario of a distributed L/C being used to calculate
Cself using Tx Line equations gives the measured DC value I found it
fascinating that the lossless case means that the DC value tracks the
Medhurst value exactly proportionately. I also found it fascinating
that using the DC value in this way gives a more realistic (higher)
value for Ctop. I wonder which of the two energy conservation tracks
more accurately? It will be interesting to find out.
Regards,
Malcolm
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.