Re: PC board primaries

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

Original poster: "R Heidlebaugh by way of Terry Fritz <twftesla-at-qwest-dot-net>" <rheidlebaugh-at-zialink-dot-com>

on 12/10/01 8:09 AM, Tesla list at tesla-at-pupman-dot-com wrote:

> Original poster: "Barton B. Anderson by way of Terry Fritz
> <twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>
> 
> Hi All - 
> 
> An idea (not sure if it's been thought of - I haven't paid close attention).
> 
> For a double-sided pc board, the top and bottom trace can be slightly
> overlapped. This would make it possible to simply etch/cut simple circlular
> traces (a gap must be cut between each circle to prevent a shorted turn). A
> feed through between upper and lower circle traces can link each turn.
> 
> Something like this: You have to use your imagination a little.
> 
> 1     3     5     7     9
> ----  ----  ----  ----  ----
> |  |  |  |  |  |  |  |
> ----  ----  ----  ----
> 2     4     6     8
> 
> Space saving as well considering this approach:
> 1     2     3     4     5     6     7     8     9
> ----  ----  ----  ----  ----  ----  ----  ----  ----
> 
> Anyway, I was just thinking about the ease of simple circles instead of a
> continuously growing traces.

AS I REPLIED BEFORE,PC board coils are subject to high frequency harminics
and require neutralizing to avoid TVI. Single sided coils work well and also
double sided coils with each winding overlaping each other. Winding to
winding capacitance is high with double sided coils and must be corrected
for. Single sided coils have extreamly low capacitance, and must be
compensated for at the other extream. Coils are made with helical winding
spirals or circular turns steped out to the next outer wind at each loop
end. Both work. square box coils work, but harmonics are an even greater
problem with lower "Q" coils. Edge emmisiom is no problem as suggested by
another TC fan. Make shure your winding to winding spacing is sufficent.
Standard 60 mill glass board will hold the output of a 15KV NST with no
problem, but keep at least 1 in from the board edge.
   Robert  H