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Re: Toroid Capacitance Equations
Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com>
John:
Can you pass along the "D" factor for the following additional sizes:
24 inch x 6
30 inch x 7
34.5 inch x 8.5
48 x 12 inch
Do you usually subtract 10% as a "shielding" factor when the toroid is atop
a coil? Typical would be coilform size = 1/2 toroid major dia.
Dr. Resonance
Resonance Research Corporation
E11870 Shadylane Rd.
Baraboo WI 53913
>
> To All -
>
> Over the past years I have collected about a dozen various equations for
the
> capacitance of a toroid. The accuracy of these equations vary greatly and
> none of them are very accurate for a particular toroid. I have found that
> having only a single equation for all sizes of toroids that give accurate
> results requires a very complicated equation. In order to simplify the
work
> of calculating the toroid capacitance I have found that 4 simple equations
> can give acceptable results.
>
> The 4 equations are for toroids with minor diameters of 3", 6", 12", and
> 20". The equations do not give the exact capacitances that Antonio's INCA
> program (meters) shows but they will be very close. In fact the equations
> will give good accuracies for minor diameters that are between the
3,6,12,20
> inch if you extrapolate between the capacitances obtained for these minor
> diameters.
>
> d = Minor diameter in inches
> D = Major overall diameter in inches
> Note that D must be at least twice d.
>
> d = 3" pf = 1.6079*(D^0.8419)
> d = 6" pf = 2.0233*(D^0.8085)
> d = 12" pf = 2.0586*(D^0.8365)
> d = 20" pf = 2.2628*(D^0.8339)
>
> The Toroid Capacitance Graph in my TC Notebook shows four capacitance
curves
> that were made before INCA's exact capacitances became available. The
> Notebook curves were made from equations that are similar to the
up-to-date
> ones shown above.
>
> If you have any questions please let me know.
>
> John Couture
>
> ------------------------------------
>
>
>