Re: Ideal Magnifier Model - PSPICE (Antonio?)

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Antonio Carlos M. de Queiroz" <acmq-at-compuland-dot-com.br> 

Tesla list wrote:
 >
 > Original poster: Rob Maas <robm-at-nikhef.nl>

 >  >Lumped model of a "Tesla magnifier":
 >  >       k12
 >  >+----+   +----+--L3--+---o output
 >  >|    |   |    |      |
 >  >C1   L1  L2   C2     C3
 >  >|    |   |    |      |
 >  >+----+---+----+------+---o ground
 >  >
 >  >C2="self-capacitance" of L2 + "self-capacitance" of L3 + "transmission
 >  >line" capacitance + other capacitances to ground at that point"
 >  >(+ guessing factor, since all this is approximate).
 >
 > Why is the "self capacitance of L3" included in C2:

We usually model a coil that has distributed capacitance and one side
grounded as a grounded coil in parallel with a "self-capacitance",
grounded too.
In a magnifier, the third coil has both ends floating. If we assume that
the capacitances from both ends of the coil to ground are identical,
the simplest model for a floating coil has then a capacitor to ground at
each end:

+--L3--+
|      |
C3a    C3b
|      |
+------+-o ground

If one end of the coil is grounded, if we assume that the
capacitances don't change due to this, the two capacitors must be
each identical to the "self-capacitance" of the coil.
And really, a measurement (or calculation) of the free-space
capacitance of a cylinder results in a capacitance that is quite
close to twice the Medhurst capacitance for a coil with the
shape of the cylinder.
Example: A coil with 32 cm of length and 4.4 cm of radius has a
Medhurst capacitance of 5.55 pF.
The free-space capacitance of an open cylinder with these dimensions
results as 10.15 pF.

 > Isn't C3 = 'self capacitance of L3' + 'capacitance of topload' on top of 
L3 ?

Yes, it is, using the "normal" copy of the self-capacitance at the
output side of L3.

Antonio Carlos M. de Queiroz