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Re: Winding vs Space-Charge Capacitance
From: Greg Leyh[SMTP:lod-at-pacbell-dot-net]
Sent: Saturday, November 01, 1997 5:53 PM
To: Tesla List
Subject: Re: Winding vs Space-Charge Capacitance
terryf wrote:
> Testing I have done on secondary coils with no top toroid suggests that
> the secondary inductor's capacitance is composed of two main capacitances in
> parallel. The first capacitance is internal to the coil winding itself and
> is probably composed of turn-to-turn capacitance. The second capacitance is
> a large space-charge region that is developed around the top end of the
> coil. The first capacitance is in the order of 0.25 pF while the second
> capacitance is on the order of 6.3 pF.
[snip]
> If this is true than it would suggest a number of possibilities to optimize
> output voltage. I am surprised that the turn-to-turn capacitance is so low.
> This is one of my non-linear wound coils but if the turn-to-turn capacitance
> is this low, I should be concentrating on field patterns and forget the
> internal capacitances.
Exactly! The total turn-to-turn capacitance is so low because they are all
in series. Most of the electrical energy is stored in the external electric
field, the sheet capacitance to ground. The challenge is in modeling this
sheet capacitance, since it is distributed along the secondary inductance.
-GL