Plasma Torid - Class E Self Resonant Dual/Stereo - Plasma Torid Build

[alan sailer]

I've had a small 1 liter xenon globe on my bench for a week or so now. It tend to be
self-starting ie nothing is needed other than turning the power supply on.

Today I moved it off my bench and to another location and the self-starting went away.
My thought was to add a ground plane underneath the coil and things got worse.

The factor that was important was the bench was wood, the new location was the surface
of a table saw which had a inch thick piece of wood over a metal ground (?).

It finally dawned on me (because I'm slow sometimes)...

...this is an RF circuit with all the weirdness that entails. Your circuit can and does include objects
nearby. It's like the issues with metal objects near a DRSSTC but even worse.

I am going to be very curious when the Chinese toroids start arriving here. Will they be as weird, interacting with
everything around them?

Time will tell.

Cheers.

[alan sailer]

Another quick note.

This part,

https://www.ebay.com/itm/115888934185?_trkparms=amclksrc%3DITM%26aid%3D777008%26algo%3DPERSONAL.TOPIC%26ao%3D1%26asc%3D20240130164827%26meid%3Df566706a3e284e0fbe2a1820bb1d87f6%26pid%3D101959%26rk%3D1%26rkt%3D1%26itm%3D115888934185%26pmt%3D1%26noa%3D1%26pg%3D4375194%26algv%3DRecentlyViewedItemsV2Mobile%26brand%3DUnbranded&_trksid=p4375194.c101959.m146925&_trkparms=parentrq%3A92bffaa618f0aab2fcf493b3fffe1ba8%7Cpageci%3A7ebfc52a-1626-11ef-9861-b66288d86e21%7Ciid%3A1%7Cvlpname%3Avlp_homepage

works just fine to start up my higher pressure (50torr) xenon globe.

I was a little apprehensive when I got the unit because another Chinese made HV module blew up a nice H/P power supply. When I hooked it up to another H/P supply and started to turn it on the OVP cut in. Seeing Deja-vou I used a battery to power it up. It ran fine and started up the toroid perfectly.

Currently I'm running it with a small wall-wart 12v@1.5 amp and it works fine. I would just recommend some caution around your supply.

Cheers.

[Hi-Deff]

Hi everybody!

I found this by accident and I'm glad I did because I haven't found many people to talk to about plasma toroids.  I built one using a 2 liter xenon globe.  This circuit is currently running on a "fake" Amazon IRFP260.  I'm going to try some different MOSFETS in the near future.  My circuit is running at 13.4 MHz.  The primary coil is very similar to Humxn's on YouTube.

I'm currently trying to figure out how to get the toroid to float in the center of the globe.  It likes to have one side sink near the coil.  I'm not sure how to correct this.  I'm using a cheap 30 VDC 5A power supply.  Maybe I need more power?  I'm not sure.  I'd like to know if anybody has any ideas.

If I adjust the current and bias just right, I get a tight toroid that centers itself right at the coil and it makes a squealing sound.  When this happens the current drops from around 2.3A to 0.8A.  However, the toroid will not float to the center.  It stays near the coil.

As a bonus, this circuit is a plasma candle circuit without the resonator coil.  I made a second coil that I can attach with an alligator clip to get a plasma candle.




 

[alan sailer]

According to humxn, the coil should be wound such that the HV (100pF) cap connection is on the bottom. Humxn also says lower current
makes the toroid float. So more power may not be the solution.

I can't tell from you picture how your circuit is arranged.

Other than that, I have no suggestions. I have two handmade one liter globes. One is 15 torr the other 50 torr.
The 15 torr "walks" around the coil. The 50 torr floats. They both use a crapload of power, 28V/3amps.

Wish I could help.

Cheers.

[Hi-Deff]

Hi Alan,

I've attached a poorly drawn schematic of what I've got going on.  The circuit assembly is point-to-point and inspired by Teslaundmehr's plasma candle.

I've got the 100pF cap attached to the bottom coil as Humxn suggested.  I requested 15 torr, so I'm assuming it's probably close to that.

I measured the value of L1 using a function generator and scope, wrote down the value on a piece of paper and then lost it.  I think it was around 15 uH, but this measurement wasn't very accurate.  That's a larger value than I've seen on most schematics.  It's 17 turns of 18 gauge around 26mm PVC.  I might try a smaller inductor.

I'm drawing around 2.3-2.5A at around 24 VDC.  If I decrease the current things get glitchy until the toroid floats near the coil.  Then, it will form a perfect toroid near the coil and lock-in that position creating a squealing sound.  The minor diameter shrinks and gets brighter.  At this point the current drops down to around 0.8 A and the toroid remains stable.  It just doesn't float above the coil.  It's at the same level of the coil.

[alan sailer]

The L1 inductor is to block the AC from the oscillator from reaching the power supply. I don't believe
 that it is a sensitive part of the circuit.

As I mentioned earlier I have two toroids, one floats, the other walks around. Why one does and the
other doesn't is a mystery to me. I tried humxn's suggestion that the electric field is what causes the
walking effect and made a coil with much wider spacing. It did not help.

Another thing to mess with is grounding. Also, for my set-up, if I have metal ground under the circuit
things go south. In my opinion, this plasma toriod demo is a very sensitive system. I'm beginning to
doubt that lessons learned from on set-up can easily transfer to another.

Good luck. I hope you find and document a solution.

Cheers.

[alan sailer]

Another interesting side effect. A beaded toroid.

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Cheers.

[Hi-Deff]

Have you seen this?  Some have speculated that there's some argon in there.  It looks like there's some metal or something at the bottom of the flask. Very cool.

https://youtube.com/shorts/8q_t78RE_-g?si=U0auvg6D6Sgl6XF7

[alan sailer]

I gave in and bought one of the Chinese toroids that you can find on AliBaba. Cost about 150$ shipped. The unit arrived with the control pot damaged but I added an external 1kohm pot and got it running. The unit works fine. I could not get the toroid to stay stable, it walks around but looks good. It runs on 24volts and under five amps.

More significantly, in 70F weather the toroid starts up without any help. No sparks, just the high frequency driver. They include a small pizo sparker (found in many cigarette lighter) that they say will start the toroid under cold conditions.

For the price it's an easy way to get a one liter xenon globe. The driver is about the same dimensions as the globe so it's pretty compact. The MOSFET is fan cooled but they still advise running it for 10 minutes maximum.

If anyone wants more details I can supply them. I don't think a video of the globe operating adds anything to what you can view all over the interwebs but....

Cheers.