Re: SSTC theory

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

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

Tesla list wrote:

 > Original poster: "Steve Conner" <steve.conner-at-optosci-dot-com>
 >
 >  >It's better to make a double L-match, performing two impedance
 >  >conversions by the same factor:
 >  >Q: 27.5
 >  >C2 = 115 pF
 >  >L2 = 21.9 mH
 >  >(These convert 380 kOhms to 500.4 Ohms)
 >  >C1 = 87.6 nF
 >  >L1 = 28.9 uH
 >  >(These convert 500.5 Ohms to 0.695 Ohms)
 >
 > If I understand correctly, an inductively coupled Tesla coil also has a
 > third untuned stage of impedance conversion, of ratio (L2:L1)^2. Did you
 > take this into account in this calculation, or are you just assuming a
 > L-match network base-feeding the secondary? Or have I got it completely
 > wrong?

In this case there is no transformer, just two L-matches in cascade:

. o---L1---+---L2---+---o
.          |        |
.          C1       C2   Rload
.          |        |
. o--------+--------+---o

C2 is the combination between the self-capacitance of L2, the
distributed
capacitance of the terminal, and streamer capacitance. Quite too large
in the example.
By using two stages, a high gain system can be built without excessively
high Qs.
The version with a transformer can be derived from a cascade of a
high-pass
L-match and a low-pass L-match, or from a band-pass filter. The cascade
above can be designed as a filter too, resulting in "maximally
resistive"
input resistance, but the design is more complex than in the bandpass
case.

Antonio Carlos M. de Queiroz