Looking at makeing a trumpet or tapered coil, (assumed benefit coupling)..
just got the capital funds working again, interested but tught on time and
resources.. more data and ideas welcome..
On Sat, Mar 7, 2026, 8:38 AM Sulaiman Abdullah <sulaiman000001@xxxxxxxxx>
wrote:
> from misty memories:
>
> The parameters of a TC at very low power can be determined entirely by
> theory,
>
> when voltage is increased there will be corona discharge that will
> significantly increase capacitances,
> this primarily occurs when a radius of curvature is less than about 1mm per
> 3kV.
>
> I am specifically thinking of the thin upper part of the trumpet coil.
> ...........................................
> I know of only two applications for a TC
> 1 edutainment
> (sparks and arcs)
> 2 transmission of power or information
> (minimal discharges)
>
> Mr. Tesla was interested in #2
> but #1 gets sponsorship.
>
> On Fri, 6 Mar 2026, 23:34 David Thomson, <aetherwizard@xxxxxxxxx> wrote:
>
> > I would like to invite technically minded builders to look at an
> experiment
> > involving a tapered ("trumpet") Tesla coil geometry and a two-channel
> > measurement method.
> >
> > The objective is to compare two quantities measured in the same resonant
> > device:
> >
> > 1.
> >
> > an electrostatic carrier derived from the topload capacitance and peak
> > voltage
> > 2.
> >
> > a magnetic-mode proxy derived from the base current
> >
> > The experiment compares how these two quantities scale as the drive level
> > and geometry change.
> >
> > Important note on geometry:
> >
> > The "trumpet" coil is a secondary whose radius gradually decreases toward
> > the top. In other words, the flare points downward toward ground and the
> > smaller diameter is at the top near the topload. The taper helps
> distribute
> > electric field stress and tends to stabilize operation before breakout.
> >
> > Measurement definitions
> >
> > Electrostatic channel
> >
> > q = C_top * V_pk
> >
> > Magnetic channel
> >
> > Q = kappa * I_pk
> >
> > where
> >
> > C_top = effective topload capacitance
> > V_pk = peak topload voltage
> > I_pk = peak base current
> > kappa = calibration factor obtained from the toroidal magnetic field
> B_phi
> > near the base region
> >
> > In the Quantum Measurement Unit (QMU) framework there is an additional
> step
> > because capacitance is inversely related to potential. The measured
> voltage
> > and current therefore must be converted through the charge conversion
> > factor (CCF):
> >
> > ccf = e_emax^2 / e
> >
> > The CCF converts between conventional charge-based units and QMU units.
> In
> > practice this means the measured potential and current channels are
> scaled
> > by the CCF before comparing the electrostatic and magnetic quantities.
> >
> > After applying the conversion, the experiment tests the relation
> >
> > Q^2 = q^2 / (8 * pi * alpha)
> >
> > where alpha is the fine structure constant.
> >
> > The extracted value
> >
> > alpha_extracted = q^2 / (8 * pi * Q^2)
> >
> > can then be examined while varying
> >
> > -
> >
> > drive power
> > -
> >
> > coupling
> > -
> >
> > secondary geometry
> >
> > If the ratio remains constant across these changes (within measurement
> > uncertainty), the two channels scale together in a nontrivial way. If the
> > ratio varies strongly with geometry, the effect reduces to conventional
> > resonator behavior.
> >
> > Required measurements
> >
> > C_top
> > V_pk
> > I_pk
> >
> > C_top can be obtained using low power resonant shift measurements or VNA
> > fitting.
> >
> > V_pk can be measured with a calibrated capacitive divider or other HV
> > measurement method.
> >
> > I_pk can be measured with a current transformer at the base of the
> > secondary.
> >
> > Calibration of kappa can be done using a small magnetic probe to map the
> > toroidal magnetic field B_phi(r,z) near the base.
> >
> > Important experimental condition
> >
> > Runs should be performed in a no-streamer regime. Once streamers appear
> the
> > electrostatic channel becomes contaminated and the measurement is no
> longer
> > reliable.
> >
> > The full experimental description is available here:
> >
> > https://zenodo.org/records/17408713
> >
> > I would especially appreciate feedback from experienced builders
> regarding
> >
> > -
> >
> > reliable high-voltage measurement methods
> > -
> >
> > practical techniques for determining C_top
> > -
> >
> > magnetic probe methods for calibrating kappa
> > -
> >
> > any pitfalls in the measurement protocol
> >
> > If anyone on the list is interested in attempting a replication
> > measurement, I would be glad to collaborate and compare results.
> >
> > Best regards,
> >
> > David Thomson
> > _______________________________________________
> > Tesla mailing list -- tcml@xxxxxxxxxxxxxxx
> > To unsubscribe send an email to tcml-leave@xxxxxxxxxxxxxxx
> >
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