Re: TC Electrostatics

• To: tesla-at-pupman-dot-com
• Subject: Re: TC Electrostatics
• From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
• Date: Fri, 13 Dec 1996 08:00:58 +1200

Bert, Richard,
                This talk of e.m. and e.s. currents is starting to 
make me wonder. I think I am seeing considerable confusion in terms 
creeping in here. Electrostatics by definition deals with non-moving 
charges.

> >However, the relatively small value of capacitance versus that of the
> >coil self-C and toroid makes a BIG change in how efficiently energy
> >couples into the secondary system, as well as detuning the system. If
> >you would have used a 5000 pF cap, the results would have been 
> >markedly different. A 50 pF cap represents 15k Ohms of capacitive 
> >reactance at 200 kHz - this makes for a _very_ lousy AC path to 
> >ground, and would kill coil efficiency even if you WERE in tune.
> >
> 
> I don't think 15k Ohms is correct.
> 
> X(c) = 1/(2pifC) = 1 /(2 x 3.14 x 200,000 x 5 x 10^-8) = 15.9 ohms.
> Actually, this is a fairly good AC path to ground.  It's a straight EM 
> shot to ground.  It's an infinite resistance to DC (up to 35 kV) AND it 
> appears to block ES current.

Bert is correct. That should be 5 x 10^-11 (pF not nF) so Xc=15kOhms 

Malcolm

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