[Prev][Next][Index][Thread]

Re: Toroid Capacitance calculated without earth-distance?

Hi Ruud,

        The closed form formula's you see are for a toroid in "free space"
without any grounded objects near by.  Someone may be able to use the
electrostatic "images" method to come up with an equation for a toroid above
ground if they really try (such things make my brain hurt ;-)).  I don't know
of anyone having done this??  Program's like E-Tesla5 take into account the
distance above ground and the distance to the ceiling and walls as well as the
primary coil.

Of course, it can be argued that the toroid equations are not accurate enough
to notice if the ground is there or not ;-)  You can use with E-Tesla5 to do a
sensitivity analysis if you are really bored ;-))

BTW - E-Tesla5.1 is a QBASIC program I wrote (with much help from Jim Monte)
that runs on any PC (eventually ;-)).  It calculates the Fo frequency of a
Tesla coil given a bunch of physical dimensions.  It can easily get within 5%
at max accuracy.  It is free and at:

http://users.better-dot-org/tfritz/site/programs/E-TESLA5.ZIP

You can open the E-TESLA5.BAS file in any word processor to print out the
program.  You can also list, change, and play with the program as you please.

Cheers,

        Terry


At 09:05 PM 04/28/2000 +0200, you wrote: 
>
> Hi all,
>  
> Maybe i missed something, but could somebody tell me how it is possible that
> in the calculation of the toroid capacitance the distance to ground is
> ignored. IMHO it should be actually inverted proportional.
>  
> Ruud.