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Re: Just a FEW questions from a newbie
In a message dated 97-01-09 01:21:04 EST, you write:
<<
Hi,
I am new to this list, and to this hobby. I am pretty good with
electronics and frequency's.
I have a few questions that I cant seem to find answers to.... so I will
throw them in the
direction of the experts... that is if you guys dont mind....
One question that I cant figure out is how do you create the frequency
to emit the magnetic
fields? Using a ignition coil switched with a 555 timer circuit would
do it. I understand that.
But with just a spark gap? How do you adjust the frequency to meet the
1/4wave on the
secondary?
For my first coil, I am looking for a design that gives off 1 foot
sparks. If I get more, that
is fine too :) What secondary size am I looking at? 2feet long by
3inches dia?
I have access to the following transformers:
24VDC in - 6KVDC out
24VDC in - 10.6KVDC out
Unfortunatally, I dont remember the current rating.. I do know they are
in milliamps.
What they are and where they came from is a mystery. Another solution
that I can
think of using would be a ignition coil off a car which would be:
12VDC in - ?????VDC out (I would have to use a 555 timer circuit to use
this one,
right?)
Which one would be the better one to use?
Capacitors. Will doornob caps work a-ok? Perhaps a few in series and
parrallel?
Where can I go about getting some? (no worthwhile hamfests in winter in
chicago)
Spark Gaps. I found some docs for a rotary one, and a stationary one.
The stationary
one looks easier for me to build is it ideal (airblast.txt)? Will an
aquarium pump work for
the air? How about an airbrush compressor?
Tank Curcuit. I have seen many different configurations for this.
Which one will
work best for my setup?
Static Gaps. I have been reading, and it appears that some of you have
more than
1 gap in your circuit. Why? Will I need more than 1? Are these
fixed?
Primary winding. Why is this tapped? Is this how you tune it? What
medium do
you suggest I use for this? Common sense tells me to make this coil
larger
than what some docs say. 5 turns of wire taped at 3 seems WAY to small
to me.
50 turns tapped at say 35 sounds more efficient to me... but that is me
:)
I have access to the following magnetic wire from Allied Electronics:
Belden Heavy Armored Poly Thermaleze high temp wire 22awg Belden8077
501ft $29.38
Belden Single Beldsol Solderable magnet wire 22awg Belden8051 254ft
$17.34
Dearborn Single Polyurethane Class A Type T-1 105 degree C 22awg
.0266"od $20.81/pnd
Dearborn Heavy Poly-thermaleze Class F type T-2 155 degree C 22awg
.0277"od 21.83/pnd
Dearborn Corona Resistant High Voltage Wire UL Style 3239 150 degree C
10kvdc-40kvdc $???
Which one do you suggest I use? 22AWG the size to go with?
How nessacary is the Choke circuits? Is the feedback going to be that
bad? I dont
see why it would if you get your SWR down enough.
Sorry for all the questions.... but I dont know where else to go!
Thanks VERY much....
Pete >>
Pete,
A good coil for the size you are looking for would be similar to the one I
just built for a December project. You can find most of the details in a
spreadsheet named Teslaexl.zip on the ftp site. It is 3.0" dia with a
winding length of 28" using #22 magnet wire. The primary is 14 turns of # 10
solid copper wire, 1/4" copper tubing would be better. You tap it to tune
the primary frequency to the self resonant frequency of the secondary. I
used a 12 kv, 30 ma neon sign transformer that I bought used for $10. The
capacitor is a home made rolled style. The spark gap is the cylidrical style
built in a piece of 6" dia pvc. The instructions for the gap and capacitors
are to be found also at the ftp site:
http://ftp.funet.fi/ftp/pub/sci/electrical/tesla.
I can provide the exact specs for you on the capacitor plate size to fit this
coil.
Ed Sonderman