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Wire length,resonance, and Q (fwd)
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From: Greg Leyh [SMTP:lod-at-pacbell-dot-net]
Sent: Saturday, May 30, 1998 6:33 AM
To: Tesla List
Subject: Re: Wire length,resonance, and Q (fwd)
[snip]
> >This is true, and devices such as waveguide stubs and antennas
> >often operate in this 1/4 wave mode. However, a TC secondary
> >_does not_ behave in this way, for the following simple reason:
> >
> >There is no actual voltage node (max V, min I) at the top.
> >
> >Although there is a current node at the base (max I, min V),
> >the top winding carries both the maximum voltage _and_ nearly
> >the maximum current, just like in a standard HV transformer.
> >This current at the top simply goes into charging the top
> >electrode, which has a lumped capacitance back to ground.
> >The current going into the arc is typically only 30 to 40%
> >of the total current being delivered to the top electrode.
> >If you change the "electrical length" of the TC secondary,
> >this will still be the case.
> >-GL
>
> Yes that's true Greg, but (lets see if say this right)
> looking at the charging of Cterm the current will lag
> the voltage by 90 degrees, Maximum I-term and
> Maximum E-term don't occur at the same time.
> I would think the phase relationship between the two
> would be much closer at the coil base.
>
> Mark Graalman
In charging a capacitor, I believe that the voltage lags
the current -- remember 'ELI the ICE man'?
If a 1/4 standing wave were present on a TC secondary with
the current node at the base, then there would not be *any*
appreciable current at the top, at any phase angle.
Measurements made by Terry Fritz, myself, and others indicate
that significant amounts of current are present at the top winding
and that these currents are in phase with the base currents,
strongly suggesting a lumped-element mode of operation.
--
-GL
www.lod-dot-org