Re: Tests: Thin wire vs. thick with fewer turns, etc.

Terry, this sounds very interesting, but how does one go about
calculating the output impedance of a Tesla Coil.

I seem to remember that that you wrote sometime, that the streamer load
is 220k + * 1pF/foot of streamer *. Is this wrong, and is the load in
all cases 220K/5pF.

Cheers, Finn Hammer

Tesla List wrote:
> Original Poster: Terry Fritz <twftesla-at-uswest-dot-net>
> Hi John,
>         From the information you give and making a few guesses, I would
> that the output impedance of your coil went from 327K ohms down to 111K
> ohms with the changes you made.
> If one assumes that a streamer presents a load of 220k in series with 5pF
> (Z=416K at 90kHz and Z=263K at 200kHz) then your old set up was probably
> impedance matched better to the streamer load than your new setup.
> Assuming a bunch of stuff, your streamers would have been receiving 225
> watts before and 140 watts now.  Assuming streamer length is proportional
> to the square root of output power (and input power too assuming more
> stuff), I would expect your new system to give streamers 80% of the length
> of the old setup.
> Admittedly, the techniques used to determine all this are a bit new and
> barely tested.  However, in your case, the results seem to follow the
> predictions.  With better streamer load data, such impedance matching may
> really help in determining what the best size and type of secondary to make
> to produce the best sparks.  I still find it hard to believe that 220K ohms
> in series with 5pF is the impedance of ALL secondary arcs.  However, it
> always seems to work in every case so far...
> Thanks for providing this valuable information!  It has great meaning to
> Cheers,
>         Terry