Re: Rectanguloids

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>

Hi Antonio, All,

Yes, I stand corrected. The resonator capacitance will increase, but 
the change in C drops off with the increase in diameter (assuming the 
minor diameter remains unchanged which is what I was getting at). I 
just ran a bunch of sims with 10" increments on the major diameter. 
Used a  4.5" coil with toroid height at 48".

I thought it would have hit a crossroad, but it didn't.

Take care,
Bart

Data of results below (fixed width font format).
--------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------
Toroid      Toroid
    % Change
Minor       Major
     Freq kHz
Diameter    Diameter   Height    Toroid C pF    Sec Ces pF    Freq 
kHz    (from previous)
6.25        21            48       21.96          25.2          234.6
       n/a
6.25        31            48       32.9           35.85         195.6
     16.62
6.25        41            48       44             47            170.7
     12.73
6.25        51            48       55.3           58.6          153.5
     10.08
6.25        61            48       66.8           70.3          140.4
      8.53
6.25        71            48       78.5           82.2          130.2
      7.26
6.25        81            48       90.25          94.3          121.8
      6.45
6.25        91            48       102.1         106.4          115
     5.58
6.25        101           48       114           118.5          109
     5.22
6.25        111           48       126           130.5          103.9
      4.68
6.25        121           48       137.5         142.5           99.6
      4.14
6.25        131           48       149           154.3           95.8
      3.82
6.25        141           48       160.5         165.9           92.4
      3.55
6.25        151           48       171.6         177             89.5
      3.14
6.25        161           48       182.3         188             86.9
      2.91
6.25        171           48       192.6         198.4           84.6
      2.65
6.25        181           48       202.3         208.3           82.6
      2.36
6.25        191           48       211.5         217.6           80.8
      2.18
6.25        201           48       220.1         226.3           79.3
      1.86


Tesla list wrote:

> Original poster: acmq@xxxxxxxxxxxxxxxx
> > Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>
> >
> > Yes, the inner ROC is the breakout level determinant from a voltage
> > standpoint. The "surface area" sets an external C which is felt by
> > the resonator. The capacitance of the resonator will increase and
> > then decrease as the OD continues outward (just gets too far away
> > from the coil itself).
>
> I think that the capacitance grows continuously with the increase of the
> outer radius of the terminal, no matter what it its shape.  The actual
> area of the terminal has little influence on the capacitance. The maximum
> distance from the center is the main factor. A sphere has the maximum
> capacitance, 111 pF per meter of radius. A toroid somewhat less, but not
> much. A "rectanguloid" would have less capacitance than a toroid with
> the same outer diameter, but not much less.
>
> Antonio Carlos M. de Queiroz