RE: The 1500t secondary myth (long)

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Steve Conner" <steve.conner@xxxxxxxxxxx>

>I haven't been following things enough to see where the 36k came from

I worked it out in the following way- According to Terry the impedance of
streamers is 220k (irrespective of the length) in series with 1pF per foot.
So as the length of a streamer tends to infinity, the impedance tends toward
a resistance of 220k. It sounds counter-intuitive but in my own experimental
work I've not found anything that would disprove this.

And Malcolm Watts argued that the loaded Q of a Tesla coil can never be less
than 6. He predicted that if you try and design one with Q<<6, the streamers
would just shrink to restore the Q to 6.

Again this agrees with experiment. It's particularly obvious with SSTCs: as
you drive them harder you reach a point where the system doesn't accept any
more power and the streamers don't get longer. At this point, the only thing
that will give more spark length is adding a bigger toroid (ie lowering Zo)

Note: this is not a quantitative proof because SSTC streamers probably have
a lower resistance and higher capacitance than Terry's 220k/1pF formula
which was for disruptive TCs. But qualitatively it seems to back up my
argument.

Putting these two constraints together means that the Zo of the resonator
should be about one-sixth of 220k. This will guarantee that streamer length
is never limited by running out of Q.


Steve C.