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

[OmGigaTron]

Greetings everyone,

Today I am building out my first post describing my work building a Plasma Torid experiment.

I will break this initial post up into a few sections, as I am hoping to use this as a repository of information, discussion, design ideas, and eventually a fully updated build log.



Picture courtesy of Zerg Labs
(Not my actual project)


// 1-2 L Borosilicate Glass Globe filled with Xenon //

A 2-liter, borosilicate glass globe, evacuated and filled with Xenon.
In the US you can find these by Wayne Strattman
https://strattman.com/
They are not listed on his official designs, but you can check his price sheets, or call him directly to ask how many he has in stock.
He only had a single 1L globe, and a few of the 2 L globes left last time I spoke with him, and lead times are 3-6 months.

EU/Russia you can contact
Zerg Labs

has quite a few options available, including pre-built with power supplies, and custom shapes and sizes.
https://teslacoil.pro/en
http://www.катушка-тесла.рф/
I do not know how the pricing, quality, or other aspects compare.
I am just trying to share other vendor options, as I know several of you are on that side of the Pale Blue Dot.

// CIRCUIT DESIGN  //

Circuit Design
This is the section that I will need the most help with, and the entire reason I am here.
Most everyone here is much smarter than I am in this, so if I do not use the correct terminology, or sound completely bonkers, just let me know.
I am here to learn, grow, and build this as a collaborative project with the community.

The initial design credit goes to Steve Ward, as his tremendous work in this field cannot be cited enough.
Class E Self Resonant Oscilitaing power amplifier

Standard Class E Self-Oscillating power circuit:
https://docs.google.com/document/d/1-jMPQOSs6-Flp181TTa8cNMSs2XumzDEahg9DVD0hKk/edit?pli=1

Sky Guided - Version .02 Circut





// Links //

The last section in this first post is a series of references to people who have created one of these builds.
This is not all-inclusive, and I know that I have missed some designs.
These are simply designs that I have found interesting and may aid in the overall development of the build and design.

BackMacSci
This was the initial design that I found.
He is younger and his circuit is one of the simplest in terms of design, but it works.
He is actively working on learning Plasma Theory and has recently also built a plasma spiral tube.
Leave it to the younger generation to inspire an old fart like myself to build new things.
https://www.youtube.com/@BackMacSci

Zerg Labs
These guys have a massive amount of work done on this topic
I am probably not giving enough credit, to them, so please check this out.
Especially for those of you on that side of the world.

https://www.youtube.com/channel/UCRKfNzc7-524yD8nlyZC5Zg

Integza
He has built one of these, but seems as if he is trying to market and sell them now as pre-built.
Looks like he is partnering with Zerg Labs as well for his build.
https://www.youtube.com/@integza

Sky Guided
This is one of the newest designs, and she is actively working on building this.
She goes into quite a bit of detail regarding the circuit design and working theory.
This is worth checking out.
https://hackaday.io/project/194683-plasma-toroid-sky-guided-pcb-edition
This is the most detailed, current, and up-to-date work on this project by anyone thus far.
If you are going to explore only a single link in this post, this is the one to read.
I learned quite a bit about the design and theory of the operation of this design from her explanations.
I should almost call this required reading.

Huxman
Only a single video here, but one of the best explanations of the circuit theory.
I would love to reverse-engineer this design and incorporate her upgrades into my circuit.
I have attempted to discern the circuit schematics, but I am having trouble with this one.
I hope there is more progress with this design.

// Further Research and optimization. //

After doing loads of reading on the circuit itself, I have found several papers where the Class E oscillator design has been iterated upon.
A few of these papers go into great detail about how to mitigate the sensitivity of components used, and how to select components to increase the efficiency.
I found several other papers as well, but they were locked behind a paywall, or in paid scientific journals.

https://www.researchgate.net/publication/326616551_A_Self-Tuned_Class-E_Power_Oscillator

https://www.researchgate.net/publication/322072074_A_Class_E_Power_Oscillator_for_678-MHz_Wireless_Power_Transfer_System

https://people.physics.anu.edu.au/~dxt103/160m/class_E_amplifier_design.pdf


// Theory //

(Warning, I may be wildly incorrect and these are simple observations based on what I have seen.
I have no supporting measurements to back any of this up.)

From what I have observed, this device works quite a bit similar to the functional relationship of the Primary and Secondary coils in Tesla coil circuits.
The exception is, that the Secondary in this case is the Glass Globe and Xenon.
With this being said, the plasma itself appears to be an inductive load, which is not a fixed figure, but its Impedance, resistance, and voltage drop can change drastically, depending on the state of the plasma.
From my work in Audio Amplifier design, this 'Load' is akin to a physical speaker to me.
It receives the driving current, it performs an action (which takes TIME) and then it changes state drastically, altering the load state.
In most Solid State designs, I have seen loads described as a single linear calculation, but in this case, we must learn as much as we can about the load we are driving, in order to properly drive it.

Some of my plans are to add things like an optical sensor, and heat sensor/thermistor, and to measure the circuit before and after the load stage, to get a better understanding of what is actually happening within the plasma.
Other things I would like to do, much later, would be to optimize the Load Time, to ensure that the circuit operates as cool and efficiently as possible.
I would then like to experiment with different waveforms, which will affect load time, as well as frequency tuning, and optimization.
At that point I am hoping to achieve a little better overall 'control' of the feedback loop of the plasma, to enable us to control/contour its size/shape/intensity, etc.


// Further Experimentation //

The reason I called this a Dual / Stereo Class E Oscillator, is that I plan on building the physical circuit twice, duplicated/mirrored.
Then I would like to build a second, secondary coil on the opposite side of the glass globe, and use the inverse of the signal from side A to Side B.
I would call this 'Stereo' in amplifier design, but no idea what the actual term for this is in circuit design.


// Closing //


I hope this has been a good read for all of you, and thank you for taking the time to read through my ideas today.
If you have anything to add, contribute, or correct, please feel free to let me know.


"Be Excellent to Each Other"
Max
Omgigatron

[OmGigaTron]

[Reserved for Build Thread]

Currently, I have received my Glass Globe.
I will also be using 1/4" / 6.35 MM OD Copper tube for my secondary.

At this point, the actual circuit I want to use is still in the design phases, but I would like to start building it soon.

So far I am simply in the design phases.


Here is a link to my ugly, work in progress, parts list at DigiKey
There are duplicates and some other parts that may or may not even work.
If anyone has any experience with any of these or would recommend something different, please let me know.

https://www.digikey.com/en/mylists/list/A3DDJ8DGUT

[OmGigaTron]

[Reserved for project write up once completed]

[Mads Barnkob]

Very thorough approach to your project and kudos for sharing everything The build up with references is as much documentation as tribute is heartwarming.

If HVF had a award for Most Well-structured Thread, this is looking like a winner!

Looking forward to follow your project.

[OmGigaTron]

Very thorough approach to your project and kudos for sharing everything The build up with references is as much documentation as tribute is heartwarming.

If HVF had a award for Most Well-structured Thread, this is looking like a winner!

Looking forward to follow your project.

Thanks for the kind words.
I figure if I am going to colaborate with others, its best to share as much info as possible.
That and I still prefer the old ways of the internet with classic forums, bbs, and the like.

I guess I better pick through my parts list, and share it with everyone to get some discussion going.

[Michelle_]

I haven’t had a chance to read all the links but I’m wondering

1. How important is the size of the globe? Will a 2” diameter one work? 1”?

2. What effect does the type of gas have, for example, can you use neon? What about the pressure of the gas?

3. Does it have to be a sphere? (Probably?)

[OmGigaTron]

I haven’t had a chance to read all the links but I’m wondering

1. How important is the size of the globe? Will a 2” diameter one work? 1”?

2. What effect does the type of gas have, for example, can you use neon? What about the pressure of the gas?

3. Does it have to be a sphere? (Probably?)

In this case, the size/shape of the globe is not directly important.
I only chose it because that is what is available, and it works for what I am building.

Wayne Strattman, whom I purchased the globe from, has a magnitude of designs, ranging from simple shapes to full-on glass sculptures.

The other reason I chose a globe, is because I intend to study the EM fields that are creating this effect, and this lets me better visualize the fields themselves.

The way this works is quite similar (but different) to standard Neon lighting and Plasma generation techniques that have been around for the past hundred years.
Neon Sign art, Florescent lighting, and that entire industry are cousins to this idea.

As for the gas inside, you could use any reactive gas such as Neon.
I chose Xenon since out of the noble gases, it has the LOWEST ionization voltage required, so I don't have to build a 50KV coil just to see results.

The pressure inside the vessel does have a direct correlation to the ease of the gasses' ability to ionize, as well as an effect of the color of the plasma produced.
This is how many Neon Sign artists can achieve different and beautiful colors.

Aside from that, I SPECULATE that a better vacuum and lower density may produce a better output with lower resistance.
I do not have much info from the Chemistry side of this equation, and I am always trying to learn more.

https://en.wikipedia.org/wiki/Xenon

https://en.wikipedia.org/wiki/Neon_lighting

https://en.wikipedia.org/wiki/Geissler_tube

https://en.wikipedia.org/wiki/Ionization_energy

https://en.wikipedia.org/wiki/Magnetic_confinement_fusion

(I am just casually working with EM Confinement Fusion, for fun)

[Michelle_]

Thanks for the reply

I have 1”x2” tubes with argon, helium, and neon, as well as a 3” diameter globe with neon. I was wondering if I could make a toroid (or something even plasma filaments) in them but I figured it would be a reach goal that I might never be able to do. I will watch this thread closely for ideas, I’d really like to try it.

[OmGigaTron]

Here is a Question regarding the copper former secondary coil.
For all of you with a multitude of Tesla Coil experiences.

I am planning on using US Standard 1/4 inch / .625 MM OD (Outer diameter) copper wire.
This is normally intended for use in connecting water to appliances etc.

It looks like TWO coils would be a good place to start, as most of the designs utilize that many.
According to the video by Huxman having the Pair, pushes the voltage toward one side, and the EM field to the other.
In theory - This is similar to the SKIN effect that I have seen on this type of copper tubing.

So, questions regarding construction, connection, length, and measurements.

Should I make two single rings, and connect them using a wire?
Or should I make a continuous loop, like Figure 8 or Oroboros, and have them cross somewhere?

When everyone here constructs a coil secondary to their tesla coils,
How do you Mechanically, and Electrically connect the coil to the circuit?
I have seen many different methods, some as simple as regular connection wire, and some such as that flat braided wire.

When measuring Inductance, How would a physical connection to the coil come into play?

What are some good spacing distances to keep the coils from each other?
I can recall reading through several different people's coil projects, that the coil spacing can play a key difference in terms of efficiency.

I am currently in the process of designing and 3D printing a few basic pieces to hold the globe in place, and I may use this as a standoff or mounting bracket for the coils.
What types of materials work best as a standoff, to isolate these coils from the enclosure/circuit/ground?
I have the ability to 3d Print Carbon fiber-reinforced Nylon.
-I read somewhere that this may be a bad idea because the CF is conductive.

If you guys can point me to links, or to threads or posts here, where you have had a good coil discussion, that would be quite helpful.
Thanks,
Max

[OmGigaTron]

Thanks for the reply

I have 1”x2” tubes with argon, helium, and neon, as well as a 3” diameter globe with neon. I was wondering if I could make a toroid (or something even plasma filaments) in them but I figured it would be a reach goal that I might never be able to do. I will watch this thread closely for ideas, I’d really like to try it.

All of those would be great candidates for this type of project.
The Neon Globe would be the closest thing in terms of physical shape and size, so once we iron out the circuit. With a few more starting volts, you could easily replicate this.

Initially several of the people who RE-DISCOVERED this in the mid-2020s, found it by accident.
Simply by placing one of those types of gass-filled vessels near a High Voltage, High-Frequency EM field.
Such as a Tesla Coil.

The Circuit I am building is simply a wildly optimized, specialized circuit to do exactly this.
But, you could use something as simple as a Spark Gap generator, a Tesla coil, or even a simple fluorescent light ballast from the hardware store.
Place it near your glass vessel, and it should show plasma.

*Theory
At this point, I am still learning about the plasma stages, and from what I can tell, there are actually 3 stages.

The FIRST step is to simply ignite the plasma, and that usually takes a single spark/em fluctuation, of a high magnatidue.

This circuit I am working on is to mold, shape, and contain the reaction in a stable state.

The third stage, which is way theoretical, is when scientists are able to 'laser pulse' / 'plasma pulse' by taking one laser emitter and using it to amplify another.
That is way beyond the stages of this design. (Until I go full mad scientist. Mwahahahah)
https://en.wikipedia.org/wiki/Hall-effect_thruster
https://en.wikipedia.org/wiki/Pulsed_laser


If you watch this video, they go into depth about the thoughts of WHY this is happening, but again, most of these are THEORY at this point.

And for those of you that need a break from the boring monotony, and want a little humor.
*Warning, This guy is a trained professional, and knows about High Voltages the danger involved, and has over a decade of history safely shocking himself.
This also goes into the theory of why our plasma toroid does what it does.

[Michelle_]

Interesting, I'm aware of making the tubes illuminate near a tesla coil which is something I intended to do. Actually making the toroid on the other hand... Good to know what I have might be useful. Tubes like this can be expensive and hard to find but I got lucky and found some interesting older pieces from someone in Ukraine.

I'm also interested in BackMacSci's filament tube which I assume uses basically the same technology.

I love electroboom, he's a genius. Integza is also very clever but if I'm understanding correctly he purchased one of the Russian toroids and didn't make it himself (?). He also nearly died making one of his last videos and is generally quite unsafe so I worry for him.

[OmGigaTron]

Interesting, I'm aware of making the tubes illuminate near a tesla coil which is something I intended to do. Actually making the toroid on the other hand... Good to know what I have might be useful. Tubes like this can be expensive and hard to find but I got lucky and found some interesting older pieces from someone in Ukraine.

That is quite lucky that you were able to purchase these tubes.
That for me was the biggest hurdle to get into this project.

I love electroboom, he's a genius. Integza is also very clever but if I'm understanding correctly he purchased one of the Russian toroids and didn't make it himself (?). He also nearly died making one of his last videos and is generally quite unsafe so I worry for him.

I have watched ElectroBoom for years, and my better half, used to show his videos in her I.T. Hardware maintenance classes.

Integza is also very clever but if I'm understanding correctly he purchased one of the Russian toroids and didn't make it himself (?). He also nearly died making one of his last videos and is generally quite unsafe so I worry for him.

I believe Integza built the one he has, he just purchased the globes from the Russian guys, (Tesla Coil Pro / Zerg Labs) Apparently, in the EU, Russia, and that part of the world, they are much easier to source.
I know that Mads and several other users on this forum are from that side of the globe, so I wanted to include the known sources for people not in the US like me.

From what I can tell, you are correct in regards to this, as most of this technology has massive overlapping parts.
This is why I am here hoping that the guys who are experts with High Voltage and Tesla Coils chime in.

[Michelle_]

Check this picture out, it doesn't look like there's all that much going on here.

https://teslacoil.pro/en/tproduct/148057938-613910514531-bublikolba-1-litr (if you enlarge the second picture it shows the exposed PCB)

I think with the information available you can definitely get there. Getting a working simulation going would probably be helpful. I'd like to look more into this but I'm trying to build an induction coil gun which is proving to be quite a challenge since I'm a HUGE NOOB!

I'm rooting for you and will be following your progress.

[OmGigaTron]

Check this picture out, it doesn't look like there's all that much going on here.

https://teslacoil.pro/en/tproduct/148057938-613910514531-bublikolba-1-litr (if you enlarge the second picture it shows the exposed PCB)

I think with the information available you can definitely get there. Getting a working simulation going would probably be helpful. I'd like to look more into this but I'm trying to build an induction coil gun which is proving to be quite a challenge since I'm a HUGE NOOB!

I'm rooting for you and will be following your progress.

I have a few designs that I have found others to build.
I might as well fire up the simulation software and get them built out.
Once I get a few values figured out, I can optimize the circuit, and finally start to build it.

[Michelle_]

Check this picture out, it doesn't look like there's all that much going on here.

https://teslacoil.pro/en/tproduct/148057938-613910514531-bublikolba-1-litr (if you enlarge the second picture it shows the exposed PCB)

I think with the information available you can definitely get there. Getting a working simulation going would probably be helpful. I'd like to look more into this but I'm trying to build an induction coil gun which is proving to be quite a challenge since I'm a HUGE NOOB!

I'm rooting for you and will be following your progress.

I have a few designs that I have found others to build.
I might as well fire up the simulation software and get them built out.
Once I get a few values figured out, I can optimize the circuit, and finally start to build it.

Great, you've inspired me to build one of these! I wasn't kidding when I said it's been on my mind. If you want any help with CAD designs or mechanical engineering I can contribute, I can also give you ready to print STL files, etc...

[alan sailer]

I watched a video about plasma toroids yesterday and saw that they were starting the toroid by using a static charge ie a plastic rod rubbed with fur. I decided to set-up my toroid and see if this works.

/>
Turns out it works quite well. I mentioned this in the YouTube video but I will repeat it here. This globe was filled by me a few years ago. It has 50 torr of xenon and works well. So higher pressures than the canonical 15 torr will work. Also I have reason to believe that baking the globe befoer filling is important. This globe was baked under vacuum for 12 hours at ~450C.

The operating power supply was initially set at 28 volts and was running at 3amps.

Cheers.

[alan sailer]

In answer to an earlier question about small toroids here is a partial answer.

https://www.youtube.com/shorts/HPjFJJj8Aag

Another answer about a neon toroid.

/>
Cheers.

[OmGigaTron]

I watched a video about plasma toroids yesterday and saw that they were starting the toroid by using a static charge ie a plastic rod rubbed with fur. I decided to set-up my toroid and see if this works.

Turns out it works quite well. I mentioned this in the YouTube video but I will repeat it here. This globe was filled by me a few years ago. It has 50 torr of xenon and works well. So higher pressures than the canonical 15 torr will work. Also I have reason to believe that baking the globe befoer filling is important. This globe was baked under vacuum for 12 hours at ~450C.

The operating power supply was initially set at 28 volts and was running at 3amps.

Cheers.

This is a great-looking setup.
I noticed that you are getting residual Plasma / Sparks when your toroid is moving, I wonder if that is an additional effect of the extra Xenon in the globe.

The way you start this globe is wild. I will have to read more on that as well.
It seems kind of like the guys who use Tesla guns and a mixture of what BackMacSci is doing, with the Triboelectric Effect.

https://en.wikipedia.org/wiki/Triboelectric_effect

[alan sailer]

I like the wand for it's emotional effect. It's exactly like doing a magic trick...

I have read about other toroid builders starting the globe by rotating the globe, creating a small static charge.
I have been unable to do this.

I also want to note that the power I am putting into this higher pressure globe is much higher than other builders.
Typically I see other use about 40 watts DC input. This one is closer to 90 watts. Gets hot quickly. I don't know if
it will hurt the globe over the long run...

Cheers.

[OmGigaTron]

So, I might as well post some progress.

I completed 3d Printing an enclosure, and a stand for my globe.
Of course, I overbuilt it.
It is roughly 200 MM x 200 MM x 100 MM
With approx 10 MM walls.
I know, it's a literal boring cube, but I am not great with Fusion 360, so I built it to what I can do.

I also included a hole in the top, and built a set of rings, that get larger, to work as a base for the globe.
At least this way, it can sit on something, and look really nice.

(Pictures)











I know these pictures are huge, I am going to see if I can scale them down a little.

[OmGigaTron]

I like the wand for it's emotional effect. It's exactly like doing a magic trick...

Cheers.

100% This is exactly the way it makes me feel.

I was so excited to show this globe to my granddaughter, and I told her PawPaw was making magic.
That is such a driving force behind this.

Because growing up, for me at least. "Plasma" wasn't really a real thing, and most science classes simply called it Magic.

So, that's what we are all doing here. Engineers by Day, Lightning Magicians by Night.
Casting Level 1 "Plasma Globe"


// Also,
an update on some of my progress outside of the actual build log:


I have also reached out to several people who have worked on this project and Recruited them over here.
Hopefully, we will hear from some others who have built this design and are working on it as well.

My goal is to get as many minds together in one place, to share ideas, so that we can all benefit from each other's work.
That way we are developing this thing with a wealth of knowledge and information.

Hopefully in the next few days, we will see a few new members chime in about their projects.

I have been quietly reading several of the builder's build logs here, and I am now certain I chose the right place to collaborate.
I have learned so much just by reading the DRSSTC builds, spark gap theory, and talking about capacitors in various threads.
Hopefully soon I will have some more to offer other than theory and ideas.

[sky-guided]

Heyo!
OmGigaTron reached out and suggested I hop into this thread

First: thanks so much for the kind words about my project! As a small correction though, using "she" would be a considerably more accurate way to refer to me.

 

[...]Getting a working simulation going would probably be helpful.[...]

This was absolutely essential for me. I spent a while in LTSpice dinking around with the circuit before anything else. Even just re-drawing the schematic was a good starting place.

I watched a video about plasma toroids yesterday and saw that they were starting the toroid by using a static charge ie a plastic rod rubbed with fur. I decided to set-up my toroid and see if this works.

Turns out it works quite well. I mentioned this in the YouTube video but I will repeat it here. This globe was filled by me a few years ago. It has 50 torr of xenon and works well. So higher pressures than the canonical 15 torr will work. Also I have reason to believe that baking the globe befoer filling is important. This globe was baked under vacuum for 12 hours at ~450C.

Oh rad, that's a clever way of getting an arc start. Also, what happens when you lower the drive power after the toroid is already running?

I'm definitely curious about other gas mixes in general.

So, I might as well post some progress.
[lots of photos]

Looking through the photos, is there any kind of insulation between the windings of your coil? (Is that just a placeholder demo coil?) Even if there is a thin lacquer or something, decent odds the voltage will be high enough for dielectric breakdown.

If I may make a minor suggestion, consider holding off on physicals layout / enclosure design until after you have a working circuit. Getting a working prototype is hard enough without trying to stuff it into a box, but once you have a circuit it's easy enough to dimension accordingly. Also, a sealed enclosure will probably cook your components.

[OmGigaTron]

Heyo!
OmGigaTron reached out and suggested I hop into this thread

First: thanks so much for the kind words about my project! As a small correction though, using "she" would be a considerably more accurate way to refer to me.

So sorry about that. I have edited my typo in my first post.

 

[...]Getting a working simulation going would probably be helpful.[...]

This was absolutely essential for me. I spent a while in LTSpice dinking around with the circuit before anything else. Even just re-drawing the schematic was a good starting place.

So, I might as well post some progress.
[lots of photos]

Looking through the photos, is there any kind of insulation between the windings of your coil? (Is that just a placeholder demo coil?) Even if there is a thin lacquer or something, decent odds the voltage will be high enough for dielectric breakdown.

If I may make a minor suggestion, consider holding off on physicals layout / enclosure design until after you have a working circuit. Getting a working prototype is hard enough without trying to stuff it into a box, but once you have a circuit it's easy enough to dimension accordingly. Also, a sealed enclosure will probably cook your components.

After I worked with my copper coils, I came to the same conclusion.
I realized that it was basically a single piece of copper with all the walls touching.
I have been toying around with 3d printing some spacers, to keep the copper tubing equally separated.

I didn't even give a thought to cooling.
Guess I'll start working on another update to my design, with some inlet power connections, and a few spots for front panel switches, pots, and other goodies.

I fired up LT spice, and have also used
https://www.falstad.com/circuit/
Because this lets me visually see what is happening in the circuit, and when it actually oscillates, I can view it.
This is my next big hurdle, as I don't have much time with simulation, so I should probably just sink a bunch of hours into tinkering with this design.

[alan sailer]

Sky-Guided asked,

Also, what happens when you lower the drive power after the toroid is already running?

What happens is if I raise the voltage the toroid edges down towards the inductor and gets smaller. Lowering the
voltage has the opposite effect. When I reach about 27 volts the toroid does a fun dance. It flickers out at the
top of the globe and then restarts at the bottom. It looks like the globe is blowing smoke rings. The twinging
noise the globe makes when it creates a toroid is a nice sound.

/>
Cheers.

[Michelle_]

 

[...]Getting a working simulation going would probably be helpful.[...]

This was absolutely essential for me. I spent a while in LTSpice dinking around with the circuit before anything else. Even just re-drawing the schematic was a good starting place.

Hi, thanks for joining and posting.

One thing I'm wondering is how did you evaluate the performance of the circuit in LTspice? Like, what were the target output parameters of the main coil, for example, that would be considered within range of success? I understand that the plasma is in essence part of the electrical circuit but I'm unsure of how, or whether, to quantify it.

Would you be willing to share your simulation file for a fair price (if so PM me, I'm an engineer and know the value of time and work!)

As for me, I inquired about the lead time of xenon globes then accidentally ordered a 2L globe since it was made "yesterday" (strike while the iron is hot as they say)

I've also obtained the schematic and details of the circuit from Zerg labs, a helpful basis for comparison to other schematics out there.

I'm interested in building a working circuit but also I want to bulletproof it with heat sinks, ducts, cooling fans etc... I have experience designing electronics enclosures as well as small ducting systems and will use thermal imaging. I will post what I'm up to once I make headway - maybe in a month or two.

[OmGigaTron]

As for me, I inquired about the lead time of xenon globes then accidentally ordered a 2L globe since it was made "yesterday" (strike while the iron is hot as they say)

I've also obtained the schematic and details of the circuit from Zerg labs, a helpful basis for comparison to other schematics out there.

I'm interested in building a working circuit but also I want to bulletproof it with heat sinks, ducts, cooling fans etc... I have experience designing electronics enclosures as well as small ducting systems and will use thermal imaging. I will post what I'm up to once I make headway - maybe in a month or two.

I'm so excited that more people are working on this project.
Congrats on grabbing one of the 2L globes.

I am also glad that there are other engineers with electronics design experience.

Most of the info that I have learned, has been in comparing different people's circuits.

[OmGigaTron]

So, today I took a stab at building out the circuit from sky-guided that I listed in the first post of the thread, and it is also in her build log.

In my own design, since I will be using a copper tube, with a possibly much greater inductance than the printed PCB coil, I will have to eventually adjust the tuning.

I have not yet added in the voltage taps, but for the most part, this looks accurate.
(I am not good at circuit design, so please, everyone chime in and let me know what I can do next to iterate and refine this design.)



If it would be helpful, I can export the design to share so others can load it up into LTSpice.

I have been doing a bunch more reading, and the "Tuning" of this circuit really has me interested.
I know a good bit about audio oscillators, such as LFOs, and circuits used in synthesizers.
This to me is kinda like that, but in the RF frequency range.
So I relate that to simply much higher OCTAVES, in acoustic signals.

I would really love to do something Musical with this circuit and somehow integrate an LFO that feeds/controls the timing of the oscillations.
This is all mostly speculation and theory, so if I am incorrect, or need to approach this another way let me know.
I just like thinking out loud sometimes.

[sky-guided]

One thing I'm wondering is how did you evaluate the performance of the circuit in LTspice? Like, what were the target output parameters of the main coil, for example, that would be considered within range of success? I understand that the plasma is in essence part of the electrical circuit but I'm unsure of how, or whether, to quantify it.

Would you be willing to share your simulation file for a fair price (if so PM me, I'm an engineer and know the value of time and work!)

Sure thing! LTspice file is attached.

Admittedly I never actually settled on what a good figure of merit for sim evaluation/optimization might be -- for me, most of the usefulness was in drawing the circuit for myself gaining some basic intuitions about its behavior rather than a true analysis. I also haven't really modeled the plasma secondary characteristics. Specific MOSFET and component values in the attached sim are different than my current revision.

Here's what's planned for the upcoming revision (schematic still a bit messy):


I haven't tested the twin parallel mosfets yet. Also, most of these components aren't a magic value or anything -- folks, please don't assume you'll need to use the same!

Once I've showcased my full finished version, I'll be open-sourcing this entire project.

[Michelle_]

One thing I'm wondering is how did you evaluate the performance of the circuit in LTspice? Like, what were the target output parameters of the main coil, for example, that would be considered within range of success? I understand that the plasma is in essence part of the electrical circuit but I'm unsure of how, or whether, to quantify it.

Would you be willing to share your simulation file for a fair price (if so PM me, I'm an engineer and know the value of time and work!)

Sure thing! LTspice file is attached.

Admittedly I never actually settled on what a good figure of merit for sim evaluation/optimization might be -- for me, most of the usefulness was in drawing the circuit for myself gaining some basic intuitions about its behavior rather than a true analysis. I also haven't really modeled the plasma secondary characteristics. Specific MOSFET and component values in the attached sim are different than my current revision.

Here's what's planned for the upcoming revision (schematic still a bit messy):
[img]https://i.imgur.com/fwVq476.png[/img

I haven't tested the twin parallel mosfets yet. Also, most of these components aren't a magic value or anything -- folks, please don't assume you'll need to use the same!

Once I've showcased my full finished version, I'll be open-sourcing this entire project.

Thank you for sharing the file, that's very nice and generous of you to share your work! It will be really helpful for me as far as learning what's going on here. I'm quite an electrical noob. I'm an automation and design engineer by trade and don't know much about actual electronics beyond industrial controls... yet.

[Michelle_]

As for me, I inquired about the lead time of xenon globes then accidentally ordered a 2L globe since it was made "yesterday" (strike while the iron is hot as they say)

I've also obtained the schematic and details of the circuit from Zerg labs, a helpful basis for comparison to other schematics out there.

I'm interested in building a working circuit but also I want to bulletproof it with heat sinks, ducts, cooling fans etc... I have experience designing electronics enclosures as well as small ducting systems and will use thermal imaging. I will post what I'm up to once I make headway - maybe in a month or two.

I'm so excited that more people are working on this project.
Congrats on grabbing one of the 2L globes.

I am also glad that there are other engineers with electronics design experience.

Most of the info that I have learned, has been in comparing different people's circuits.

I'm excited about it too, when I first saw a video of one of these I thought I probably wouldn't ever be able to build one but here we are.

[alan sailer]

So a few minor facts to add to the information pile.

Background, I have an old xenon globe at 50 torr that I filled long before any toroid frenzy. It
makes a good but hot toroid display.

I ordered a few more globes and filled them with 15 torr and then 50 torr xenon. No toroid
behavior. I began to wonder if baking was the difference. So I build a sketchy oven and baked a
one liter globe at 350C for an hour. Filled it with 15 torr of xenon.

Observations.

The new globe is super easy to start using the static trick.

The lower pressure globe uses less power. Still not low as some others have noted but I will not
say that my drive circuit is well tuned.

The ring in the lower pressure globe is not stable. It "attaches" itself to the coil and rolls around.

huxmans observation that the winding direction of the output coil is important is true. If I flip my
coil I can't get anything. It is pure luck that I got the right "polarity".

[OmGigaTron]

So a few minor facts to add to the information pile.

Background, I have an old xenon globe at 50 torr that I filled long before any toroid frenzy. It
makes a good but hot toroid display.

I ordered a few more globes and filled them with 15 torr and then 50 torr xenon. No toroid
behavior. I began to wonder if baking was the difference. So I build a sketchy oven and baked a
one liter globe at 350C for an hour. Filled it with 15 torr of xenon.

Observations.

The new globe is super easy to start using the static trick.

The lower pressure globe uses less power. Still not low as some others have noted but I will not
say that my drive circuit is well tuned.

The ring in the lower pressure globe is not stable. It "attaches" itself to the coil and rolls around.

huxmans observation that the winding direction of the output coil is important is true. If I flip my
coil I can't get anything. It is pure luck that I got the right "polarity".

This is exactly the kind of observation that I was hoping for when I started this thread.

THEORY / HYPOTHESIS
From everything I have seen, the Theory involved acts similar to a standard transformer, in the way that most of these Tesla Coil builders make a primary and secondary,
But, in my hypothesis, and as the observations of others, the Magnetic field has a far greater effect than the voltage, or current moving through the coils.

In this case, the magnetic field is acting as a containment for the plasma inside the globe.
It also from what I can tell, when oscillating at the resonant frequency of the plasma, keeps the actual plasma reaction going and stable.

From what I can tell this is why when the voltage is adjusted, the oscillating frequency, between the coils and plasma changes.

From what I have read, regarding Zero-Volt Switching, when the CLASS E Oscillator circuit, is fine-tuned, there is only a small amount of voltage, but the circuit, OSCILATES in tune with the secondary in this case the plasma.

[sky-guided]

So a few minor facts to add to the information pile.

Background, I have an old xenon globe at 50 torr that I filled long before any toroid frenzy. It
makes a good but hot toroid display.

I ordered a few more globes and filled them with 15 torr and then 50 torr xenon. No toroid
behavior. I began to wonder if baking was the difference. So I build a sketchy oven and baked a
one liter globe at 350C for an hour. Filled it with 15 torr of xenon.

Observations.

The new globe is super easy to start using the static trick.

The lower pressure globe uses less power. Still not low as some others have noted but I will not
say that my drive circuit is well tuned.

The ring in the lower pressure globe is not stable. It "attaches" itself to the coil and rolls around.

huxmans observation that the winding direction of the output coil is important is true. If I flip my
coil I can't get anything. It is pure luck that I got the right "polarity".

This is exactly the kind of observation that I was hoping for when I started this thread.

THEORY / HYPOTHESIS
From everything I have seen, the Theory involved acts similar to a standard transformer, in the way that most of these Tesla Coil builders make a primary and secondary,
But, in my hypothesis, and as the observations of others, the Magnetic field has a far greater effect than the voltage, or current moving through the coils.

In this case, the magnetic field is acting as a containment for the plasma inside the globe.
It also from what I can tell, when oscillating at the resonant frequency of the plasma, keeps the actual plasma reaction going and stable.

From what I can tell this is why when the voltage is adjusted, the oscillating frequency, between the coils and plasma changes.

From what I have read, regarding Zero-Volt Switching, when the CLASS E Oscillator circuit, is fine-tuned, there is only a small amount of voltage, but the circuit, OSCILATES in tune with the secondary in this case the plasma.

With these self-oscillating "Class E" drivers, frequency doesn't much change when drive power is changed. The oscillating frequency is determined by the resonance of the LC circuit, given as

Code: [Select]

f₀ = 1 / (2pi * √(LC) ) It does make a bit of a difference whether the toroid is currently arcing (and where its floating) since that has some effects on the coil's inductance, but it's not the kind of feedback you suggest. The magnetic field is a consequence of the moving charges in the coil. And to be clear there's no "plasma reaction" -- the xenon isn't fundamentally changed in any way; it's a very similar phenomenon to the traveling arc of a jacob's ladder  where the already-ionized air is a path of lower resistance for subsequent arcing.

I'm fairly sure that this specific topology of self-oscillating drivers isn't at all required for the toroid effect; they're just convenient to make and don't require fiddly manual tuning. (Compare: the popularity of the "slayer exciter" and "mazzilli driver" high voltage sources.) I also feel like "Class E" is a bit of a misnomer here.

If one were to seriously study what's going on here in terms of plasma physics, the correct approach would probably be some combination of finite element analysis and actually waving around a field strength meter. Or even better, actually reading the original research papers that BacMacSci cited.

As a potentially more approachable experiment, I'd love to see what'd happen with drive frequencies outside of the now-customary 10-15MHz range.

[alan sailer]

sky-guided,

I agree about the frequency "stability". I have not spent lots of time watching the frequency vs bias. But when I did the frequency
did not vary (to first order) with bias change. And as I understand (which is very basic) the resonant frequency is the LC time constant.

I tried winding another coil more like huxman, with the high voltage (kV) junction of the LC on the bottom. It did not seem to make
the toroid more stable but I was shocked at one bias point when the toroid just spontaneously popped up. No start action required. It makes
a cute squeal and then starts it's wandering ways.

/>
This is one weird little interacting mess of electromagnetic effects.

Cheers.

[davekni]

I ordered a few more globes and filled them with 15 torr and then 50 torr xenon. No toroid
behavior. I began to wonder if baking was the difference. So I build a sketchy oven and baked a
one liter globe at 350C for an hour. Filled it with 15 torr of xenon.

Baking under vacuum is the ideal glass surface degassing process.  Neon sign makers use a process they call "bombarding".  It's not quite full vacuum because 2-3 torr of added gas is needed to pass high current through the tube to cause the heating.  Not clear if the hot plasma inside helps degassing or hurts it.

But, in my hypothesis, and as the observations of others, the Magnetic field has a far greater effect than the voltage, or current moving through the coils.

As a potentially more approachable experiment, I'd love to see what'd happen with drive frequencies outside of the now-customary 10-15MHz range.

A relatively high electric field is needed to start internal xenon glow discharge.  A lower field and higher current maintains the discharge (torus).  The starting electric field is usually capacitively coupled to xenon through tube wall, from a starting wand or from coil voltage.  Sustaining electric field is almost all induced by the AC magnetic field, which is why the discharge is a torus.  Not clear if the magnetically-induced electric field is ever high enough alone to start discharge.  That's something I hope to experiment with some day, using a single-turn coil (high current at relatively low voltage) to minimize capacitively coupled electric field.
Frequency will be a great variable for experimenting.  Lower frequency will require more current (stronger magnetic field) to induce the same electric field.  That stronger magnetic field should push the torus farther from coil due to stronger magnetic repulsion.  Farther from coil will reduce electric field.  May result in more self-extinguishing and restarting.  I expect high frequency will be most efficient at generating a stable torus close to coil.
Of course, buoyancy of of the hot torus also causes it to rise.  One of the videos shows the significant behavior difference between coil on top vs bottom of xenon-filled glass sphere.  With coil on top, torus is stable and closer to coil.  Don't recall which video shows this.

[OmGigaTron]

I finally ordered parts this week.
I have been working with Tate, (BackMacSci) and finally got everything ironed out.

Here is the circuit that I will be attempting to build:
https://www.circuit-diagram.org/circuits/24ddc75d2c05422cb0dfbe5f598448c6

Parts List:
https://www.digikey.com/en/mylists/list/6DCYSXEZJK
Total cost per unit is ~20$
I ordered some magnet wire, and I will have to wind the secondary to tune the circuit, but everything else is on that list if anyone wants to replicate this build.



I also pulled out a few of my EE Theory books, and have been reading them.

Sorry about being so quiet lately, Real life has been pretty busy.
But hopefully, I will be able to add some actual updates and contribute a bit more to this build with some real measurements.

I hope everyone has a most excellent week.
-Max

[Michelle_]

Check out what I found, there are mini plasma toroid generators and gas globes on aliexpress now:

https://www.aliexpress.us/item/3256806678903018.html?spm=a2g0o.store_pc_home.0.0.5f617d84Qz3GxW&gps-id=pcStoreNewArrivals&scm=1007.23409.271287.0&scm_id=1007.23409.271287.0&scm-url=1007.23409.271287.0&pvid=6decdcb1-6444-48cb-974b-92feb59ace40&_t=gps-id%3ApcStoreNewArrivals%2Cscm-url%3A1007.23409.271287.0%2Cpvid%3A6decdcb1-6444-48cb-974b-92feb59ace40%2Ctpp_buckets%3A668%232846%238108%231977&pdp_npi=4%40dis%21USD%2165.39%2165.39%21%21%21470.06%21470.06%21%402103297417151892807003769e32cb%2112000038817558759%21rec%21US%211653574204%21&gatewayAdapt=glo2usa

https://www.aliexpress.us/item/3256806669523156.html?spm=a2g0o.detail.pcDetailTopMoreOtherSeller.4.ec63H3YtH3YtEv&gps-id=pcDetailTopMoreOtherSeller&scm=1007.40050.354490.0&scm_id=1007.40050.354490.0&scm-url=1007.40050.354490.0&pvid=9709064f-d643-43e5-8869-5c45b5219357&_t=gps-id:pcDetailTopMoreOtherSeller,scm-url:1007.40050.354490.0,pvid:9709064f-d643-43e5-8869-5c45b5219357,tpp_buckets:668%232846%238108%231977&pdp_npi=4%40dis%21USD%2185.13%2185.13%21%21%21612.00%21612.00%21%402101e7f617151892895093313ecccc%2112000038526756379%21rec%21US%211653574204%21&utparam-url=scene%3ApcDetailTopMoreOtherSeller%7Cquery_from%3A

[Lasr8]

This is a great thread, happy that I've found it! Im very interested in trying to figure this circuit out and build one. Already this is some great info on the topic. I've purchased one of the xenon globes and now I'm trying to get the other components together, looking forward to this journey with yall.

[alan sailer]

A quick note. As huxman observed in their excellent video, grounding is very important variable in this
rather temperamental circuit. I had a good self starting circuit on a 15 torr glass globe that stopped
self starting. The ground lead had slipped from the heat-sink.

Another note is that this darn thing always seems to be operating on the edge of reliability. Changing
even apparently insignificant things can take you out of the realm of operation.

Good luck!

Cheers.

[OmGigaTron]

I started this project with a fire of motivation,
Sorry that I have not updated in a while,

I finally have all the parts and this weekend. I solved the heat sink issue.
I will be working on assembly and prototyping the physical layout soon, and after reading about so much work here done with High Voltage busses,
And especially Alan talking about grounding, I want to get this part right, and reliable.

Once I get a few pictures of the setup I will update with more.
I am still quite excited to work on this project, even if I work at a turtle pace compared to most others.

[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.