Re: Hybrid Coil (was Coil Efficiency)

From: 	Greg Leyh[SMTP:lod-at-pacbell-dot-net]
Sent: 	Friday, August 01, 1997 4:04 PM
To: 	Tesla List
Subject: 	Re: Hybrid Coil (was Coil Efficiency)

Tesla List wrote:

> > If in PSPICE an appropriate capacitor (7.5 nF for my coil) is connected
> > across the lower 1/12 of the secondary on a standard coil, then the
> > operation of the coil is almost identical to that of a magnifier, according
> > to PSPICE.  This is because the K values between the primary and the lower
> > 1/12 of a secondary of a typical coil are around 0.4, whereas coupling to
> > the upper 1/12 may be less than 0.01.  The point where the 7.5nF cap is
> > connected defines exactly where the 'tap' is along the secondary.
> >
> > I propose calling this arrangement a 'hybrid coil', as it is not a pure 2 coil
> > system (due to the secondary tap) nor a 3 coil magnifier (finite coupling exists
> > between the primary and 'free resonator').
> >
> > -GL
> How did you determine the value of the capacitor? (guess - Xc gives a
> resonant condition at natural Fr for the 1/12 portion of the line?).
> I've got to try this.
> Malcolm

Good guess!  Yes, that was my starting point, then I played a lazy game 
of hi/lo in PSPICE, until the output voltage was optimized.  Since the 
pentium takes only a few seconds to do the simulation, this was far faster 
(and probably more accurate) than me thinking about all of the various
coupling effects on the cap value.