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

Re: toroid parts...

Tesla List wrote:
> 
> >From chip-at-poodle.pupman-dot-comThu Aug 15 21:17:52 1996
> Date: Thu, 15 Aug 1996 21:11:32 -0600 (MDT)
> From: Chip Atkinson <chip-at-poodle.pupman-dot-com>
> To: Tesla List <tesla-at-poodle.pupman-dot-com>
> Subject: Re: toroid parts...
> 
> >>>
> Hi All -
> 
> Has anyone tried to test these duct toroids for capacitance to compare
> them
> with spun aluminum toroids? They appear to have very low capacitance.
> 
> John C.
> <<<
> 
> My vast electronic experience says "how can that possibly be true?"*
> I always heard that capacitance is a function of surface area, not
> necessarily material.  Perhaps what you are thinking of is that the duct
> toroids aren't as smooth, and thus would dissipate their charge much
> faster than a smoother spun toroid.
> 
> I also had the idea that a duct toroid is "virtually" smooth because the
> size of the defects (ridges) are much smaller than the wavelength at that
> frequency.  At least that's my understanding from what light does.
> (Someone Pleeease correct me if I'm all wet here)
> 
> Chip
> 
> *I had enough college physics to realize that it wasn't the major for me.
>  Now if I can't fix it by cycling the power, I'm almost stumped :-)


All,

Chip is absolutely correct, of course.  Surface area is the factor for 
isotropic capacity, not shape, material or surface finish.

The electrostatic linkage between any top terminal and a resonator is 
extremely complicated and at least 5 factors can alter the final realized 
capacitance of the all-up running capacitance actually realized by the 
system's terminal load.  Two of these factors aren't knowable to the 
experimenter for calculation purposes.  (Air or ion cloud load 
capacitance- varies with power,temp, pressure, surrounding objects, and 
surface breakout factor for the particular geometry- directly affects ion 
loading capacitance level).  All the other factors are calculable with 
any standard computer and solid input data. (No one ever seems to have 
solid input data, though.-problem with the builder/user, not the CPU). 

Richard Hull,TCBOR