From: "Malcolm Watts"
Date: Thu, 5 Aug 2004 17:21:07 +1200
Subject: Re: [TSSP] Secondary dynamic Efield
Hi Marco,
On 4 Aug 2004, at 11:21, Denicolai, Marco wrote:
> Hi Paul,
>
> I'm getting acquainted with HV resistive dividers. I tested my first
> one and got proof of its poor performance. What actually spoiled it
> was its 10 pf stray capacitance to GND. I got a step response of 30 us
> (!). Some would say easy to guess for a resistance of 1.2 Mohm.
>
> Hanging the divider at 3 m height will sure reduce its capacitance to
> gnd. That was my original plan. But now I learnt that any
> discontinuity in the Efield even AROUND its water column will result
> in unbalanced stray capacitance and, therefore, in slow step response.
>
> I'm reluctant to place the divider inside the secondary because it's
> difficult to mount it and service it there. But there the Efield
> should be pretty constant. But... Now comes my question.
>
> If I recall you and Terry produced some nice dynamic plots of the
> secondary voltage and current. Wasn't it so that they were varying at
> the secondary frequency? That would imply not constant dynamic Efield
> distribution inside the secondary and make the probe placement there
> definitevely a bad idea. Am I right?
If not there then where? Anything external is going to distort the
external e-field sin't it? At least if the probe is centred, the
field is equally skewed inside the resonator and the external field
is largely undisturbed. One can remote e-field checks on the
difference/s the probe might be making.
BTW, I should perhaps have directed my recent experiment
wishlist to TSSP rather than the builder's list. I suppose that it
was predictable that an exacting enquiry would be watered down and in
one case, reduced to banality.
Malcolm
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.