Plasma Sphere / Projects / Forums

Forums

4hv.org :: Forums :: Projects

« Previous topic | Next topic »

Plasma Sphere

Move Thread

LAN_403

GluD

Mon Jan 02 2012, 09:08PM

Registered Member #1221 Joined: Wed Jan 09 2008, 06:17PM
Location: Odense, Denmark
Posts: 196

Hello all

I recently finished this project and decided to write a little about it here in case someone may be interested in plasma spheres.

The goal of this project was to make a plasma display in a 2L round bottom flask in which the gas could easily be changed to a new pressure or a new gas. Ordinary plasma spheres or globes, usually work at a much lower pressure but I could not find a way to allow for such low pressures with the equipment and tools I have. So I compensated for the higher pressure with a higher voltage.

The gas system is described here in an old thread

At the moment I only have Argon and Neon at my disposal, it turned out Krypton and Xenon were too expensive for me.

The electrical system is very simple. A NE555 driving a IRFP450 which drives an ignition coil, the power is supplied by a torodial transformer with two 18 volt outputs joined together for 36volt.
The white sheet in the second picture is PTFE sheeting to insulate the rest of the circiut from the high voltages. Maybe not the best way to do insulation but it works and the generation of ozone is surprisingly low. I had alot of problems with arc overs inside the box but I managed to find a voltage at which it only breaks out inside the glass flask where the pressure is lower than the atmospheric pressure.

The gas system is supposed to fit onto the 'socket' which is seen in the second picture in the middle of the white PTFE sheetings. Thus it is very quick to remove and replace the gas system each time I need to change the pressure or composition of the gas.

All the plasma here is with Argon, when I have time for some more experiments I shall see if I can capture a few pictures of a Neon plasma to supplement the Argon pictures. In the last pictures the pressure is very high I think something around 700 or 800 mBar, not far from atmospheric pressure. It is a very brilliant white colour in reality but my camera dont pick it up well. I suppose I shall have to purchase a proper camera

I will problably add more pictures or video when I do more experiments.

Tetris

Tue Jan 03 2012, 02:31AM

Registered Member #4016 Joined: Thu Jul 21 2011, 01:52AM
Location: Gainesville, FL
Posts: 660

It's very pretty but is the globe safe to touch?

GluD

Tue Jan 03 2012, 12:12PM

Registered Member #1221 Joined: Wed Jan 09 2008, 06:17PM
Location: Odense, Denmark
Posts: 196

HighVoltageChick wrote ...

..is the globe safe to touch?

Not really, but as I prefer to sit in my chair and watch from a distance I dont consider it a problem.

Mads Barnkob

Tue Jan 03 2012, 05:42PM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

Did you ground the other end of the HV transformer? When I made a ghetto plasma globe it would only work properly if I had one end grounded to earth.

Looks good GluD, its nice to build things that you can lean back and relax to :) Now all you need is a tube amplifier!

GluD

Tue Jan 03 2012, 07:19PM

Registered Member #1221 Joined: Wed Jan 09 2008, 06:17PM
Location: Odense, Denmark
Posts: 196

Mads Barnkob wrote ...

Did you ground the other end of the HV transformer? When I made a ghetto plasma globe it would only work properly if I had one end grounded to earth.

Looks good GluD, its nice to build things that you can lean back and relax to :) Now all you need is a tube amplifier!

My house is from the 60's and doesnt have ground in the wall sockets so it wasnt an option to ground it. I just run it with enough voltage to break out anyway. The ignition coil used to arc over in the atmosphere but I got that under control now.

The leaning back & relaxing part is very important indeed

and belive it or not I am actually considering making a single ended KT88 amp sometime, but there is so many other projects....

Tetris

Tue Jan 03 2012, 10:13PM

Registered Member #4016 Joined: Thu Jul 21 2011, 01:52AM
Location: Gainesville, FL
Posts: 660

GluD wrote ...

and belive it or not I am actually considering making a single ended KT88 amp sometime, but there is so many other projects....

O_O you don't have grounded outlets? .............

Fulmen

Tue Jan 03 2012, 10:58PM

Registered Member #3883 Joined: Fri May 13 2011, 06:30PM
Location: Norway
Posts: 87

Very nice work, Sir. I have a "real" one bought 20years ago, still works and still a joy to look at. If I get my hands on a RB flask I just might try it myself, I'm sure you'll have plenty of fun with that thing.

GluD

Wed Jan 11 2012, 03:47PM

Registered Member #1221 Joined: Wed Jan 09 2008, 06:17PM
Location: Odense, Denmark
Posts: 196

As promised here is a picture of a Neon plasma, I think it is much better than the argon.
Again I must apologise for the poor quality of the picture.

1326296362 1221 FT131388 Neon Plasma 005

I noticed something odd though, aperantly the driver circuit and ignition coil heat up considerable more with Neon than it did with Argon at the same pressure.

The pressure is approximately half an atmosphere.

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob