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Re: Whoo-hoo! (and some questions)
On Tue, 27 Jun 2000 23:21:31 -0600 "Michael Novak" <acmnovak-at-msn-dot-com> (by
way of Terry Fritz <twftesla-at-uswest-dot-net>) writes:
> Whoohoo! The list is back!
> I have a billion questions scraping the back of my brain and i need
> some
> answers
> : |
> Of course, I don't plan on asking all of them at once... here's
> what's most
> recent...
> Okay-
>
> 1.)What happened to R Coppersmith and WinTesla? I need a copy for
> my new
> system and his site is down! Can anyone help me out?
>
> 2.)For those of you who build plasma globes and discharge tubes, do
> the arcs
> inside a vacuum get really hot? I'm making a flat discharge tube 4
> inches
> wide(10cm) by about 26 inches tall (65cm) and I need some tips on
> general
> construction.
That's quite the plasma display... ...My experience has been the that
the arcs -are- hot, but not very. Nearly all of my plasma "globes" have
been made using glass, and have never had a problem with any heating. My
hands to geet a bit warm if I press them against one of the smaller ones,
but I think that that is from RF heating of my flesh, as the glass is
cool to begin with. Perhaps it is capacitive grounding of the HV though
the glass, and in that case it very well may be a problem.
> A.)What kind of adhesive would be best for sealing it as far as
> pressure,
> flammable vapors, and heat goes?
I have made semi-permenant seals using hot glue, silicone sealant, and
epoxy. Th elast two seem to work the best. I have heard of people
geetting green or blue arcs from the usagee of silicone, but I have
neveer experienced this. I have only used stuff that cured with acetic
acid (vinger type smell).
I was thinking something along the
> lines of
> 100% silicon caulk, but when it dries it gives off some nasty vapors
> (smells
> like ammonia). On a previous plasma globe, I used clear caulk (not
> necessarily
> silicone) and the discharge turned blue-green and made the inside of
> the globe
> get real smoky. And it smelled worse than anything imaginable : P
Yikes! Did you allow time for it to cure completely? I usually have let
plasma globes sit for -at least- a day or two before pumping them down
and powering them up.
> B.)Would a direct soldered copper tubing line from the
> compressor to the
> enclosure be the best for the vacuum?
Probably, but I have just used a length of vinyl tubing in the past. You
don't need that strong of a vacuum for things to work OK.
Also, what kind of stopcock
> could I use?
I have no idea. I'vee neeveer used one. I usually just pump it down for a
while, keeping an eye (well, hand) on the airflow out of the pump
exhaust, then apply power as a test to see if the vacuum neeeded has
been reached. Once I am saitisfied with the discharge, I usually just
turn the pump off for a while, turning it back on in intervals.
List: Could this hurt the pump? It is a conveerted air compressor from a
very old refridgerator
> Could it be a cheapo neadle valve for plumbing or does it have to be
> a glass
> vacuum stopcock with vacuum oil and whatnot?
> C.)What pressure is required for a good globe? My guage only
> goes from 0-30
> inches of mercury which isn't very accurate, but hey, it only cost
> 2 bucks. My
> vacuum pump, an old a/c compressor, hasn't been giving a very good
> vacuum
> lately. How could I improve upon this?
I don't know. I have heard that the pumps from air compressors are lees
robust and more prone to failure if pressed into vacuum pump service than
those from fridges.
> D.)What kind of power supply is best?(quite specifically) I have
> tried the
> 2n3055 circuit, but that gave somewhat low voltage (12kV) and high
> current
> (2-5mA).
I usually use a single-transistor 2n3055 circuit to drive a flyback,
which seems to reliably give as much as 40kV at a few mA. It works fine.
The circuit is pictured on the flyback section of my page:
http://www.electrophile.8m-dot-com/flyback.htm
I'm thinking something along the lines of a solid state tc
> maybe? Can
> anyone point me to a good (idiotically simple) circuit for one?
>
> 3.)Are solid state coils "pc-friendly"?
Certainly Not! They produce just as much RF output, perhaps cleaner and
over a less broad spectrum, but they still can cook your expensive
machine into a mostly useless pile of plastic, glass, and metal.
>
> 4.)I need a *really* cheap mmc! However, I have no clue where to get
> such
> capacitors... Could someone hook me up with a couple hundred caps? I
> need to
> end up with 30kV -at- .04uF(40nF) pLeASe HeLP mE!!!
Well, Terry probably has some more of those ubiquitous PP caps he has so
lovingly provided at a bulk discount cost to the list in the past....
>
> 5.)Could a DC-TC rotary spark gap become synchronous simply by
> adjusting the
> speed correctly? I mean, to adjust the break rate to the rate at
> which the
> capacitor is charged and ready to fire.
That could be accomplished, I suppose, but the stability of RPM needed
probably would require the ilk of a servo motor.
> 7.)Could a 100 gallon aquarium be turned into a big ol' plasma
> globe? I have
> one(100 gal aquarium) which serves as a "capacitor zoo", it had, at
> one time,
> around 150 huge electrolytic caps in it... fun stuff.
Yesssss.... ....but you would need to use the right kind of gasses so
as to not have to operate under vacuum. I doubt the glass walls would
tand up to the pressure.
> 8.)What kind of gases produce what kind of effect in discharge tubes
> or plasma
> globes?(i.e.- air makes wussy pink arcs)
Any noble gas, specifically, neon or argon (krypton, Xenon, Radon,
Helium). Mercury vapor works, but it is heavy with UV. Argon is readily
available from welding suplly places, but the cost of the regulating
equipment and tank is prohibitively expensive. Make friends with somone
who has a TIG or MIG welder, and likes to use a strait argon mix.
Sometimes, a 80/20 argon/CO2 mix is used, and this will do nothing in a
plasma globe.
> F.)What the heck is gutta-percha anyway?!
I believe it is a type of rubber-like coating. Today someting like PVC
would be a vast improvement.
> G.)Does the "phantom streamers" effect really work? That looks
> awesome...
I've observed something like it from a small coil running at a low pulse
rate, with a light-shielded SG, just below the breakout point, in
cmoplete darkness.
>
> Please help me out... this kind of crap has been getting on my
> nerves.
> Thanks soo much in advance...
>
>
> -Michael
>
>
I hope that I helped, some.
-Grayson
>
>
> P.S.S.- Has anyone in the list ever played "Half-Life : Opposing
> Force"?
> There's a big ol' Tesla Coil powering the electric fence in tthe
> demo...
> however, the arcs are coming off the bottom for some reason. And you
> can walk
> right up to it while it's on, and hit it with a wrench. I wish I
> could do that
> sometimes... ; )
> Later
>
>
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