[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: ScanTesla7.62 :-))
Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>
Hi,
I am not too surprised the streamer capacitance is a little higher in
the small grounded area he was in. Just like the coil itself,
streamer capacitance depends some on the surroundings. For 36 inch
arcs and a 8 inch topload"
C = (36 - 8) / 6 = 4.66pf total or 1.55pF/foot But Steve was getting
2.7pF/foot.
The frequency drops from 62.7kHz to 56.3kHz which is mostly
capacitive. If the secondary is 10" x 30", 1700 turns, that works
out to 209.4mH.
C1 = 30.77pF C2 = 38.16pF So the difference is 7.4pF or 2.46
pF/foot. The added roughly 1pF/foot is within what one might expect
given the streamer's surroundings. For the 100k vs. 220k
difference... I have no idea... Of course, if Steve's numbers work
better, use them!!
Gerry said:
Hi Terry and dest,
An additional question is why is the 100K (Terry's 220K) in series
with the added streamer capacitance and not in parallel?? It seems
like two affects are happening. One is a frequency reduction and
the other is a Q spoiling effect. Attaching an added capacitor to
ground will effect the frequency reduction and adding a resistance
to ground will spoil the Q.
It might be possible to model it that way. The case of no streamer =
no load would make both values dependent on streamer length.
In a "real" streamer, is it not the case that the streamer channel
is relatively low resistance so the streamer capacitance shows up as
additional capacitance to ground for the topload?? And is it not
the case that most of the power being dissapated in the streamer is
at the streamer tip where the streamer is "burning" a new path??
Yes.
If the Q spoiling was constant with streamer length, then R in
parallel with C may be the right topology. If the Q spoiling was a
function of streamer length, then maybe having R is series with C
would be the right topology.
Perhaps. The model I use is all based on this:
http://www.pupman.com/listarchives/1998/October/msg00290.html
Cheers,
Terry
Gerry R.
At 01:11 PM 6/11/2006, you wrote:
Hallo Terry, it looks like you are not receiving some messages too, so i
repeat one of them : )
> > Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>
> But "right now", there is the model of "1pF/foot+220K" and the
> dynamic (the "first" dynamic) model, at least for coiler's...
> I am sort of amazed at how long and successful "1pF/foot+220K" lasted
> and still rules today (five years...)!!!
how about this:
http://www.scopeboy.com/tesla/experiment/index.html
"Using Terry Fritz's idea of a fixed resistance in series with (X pF
per foot) I get 100k + (2.7pF/foot) which is not really anything like
Terry's 220k + (1pF/foot). Are my calculations wrong? Is Terry's model
wrong? Or are Scottish streamers just thicker and hairier?"
who is rules today - Dr. Mc Steve or Terry? : ) and what was the real
reason for 100k & 2.7pico?
-----
Let the bass kick! =:-D