YOU CAN BUILD YOUR OWN FLOATING RING OF PLASMA IN A GLASS SPHERE
A glowing purple-white ring of plasma floats freely inside a glass sphere, touching nothing — held only by an electromagnetic field.
by Simon Liu
ScienceWorkshop
- difficulty
- ●●●●○
- time
- a weekend-plus
- license
- CC-BY-NC-SA-4.0
- repo
- repo ACTIVE144 stars
●●●●○ · a weekend-plus · CC-BY-NC-SA-4.0 · 144 stars · repo ACTIVE
WHAT YOU’LL NEED
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COMPAREE VERDICT
This is a plasma toroid generator — a floating ring of ionized xenon inside a sealed glass bottle, driven by a radio-frequency field from a coil underneath. The effect is magnetic: purple-white light, no contact, a miniature cousin of fusion tokamaks. The circuit is a self-oscillating class-E oscillator running at about 10 MHz, built around an IRFP260N MOSFET. Simon Liu's design is complete — Gerbers, BOM and a photo-by-photo tutorial in four languages — and the hardest-sounding part is solved for you: the 80 mm glass bottle comes pre-filled with low-pressure xenon from the creator's store, so there is no vacuum work at all. What you do is solder the driver board, wind a four-turn coil through a PCB bracket, mount the MOSFET on its heatsink and power it from a current-limited 24 V supply. The single biggest trap is soldering quality: the author says most failed builds come down to bad joints, and skipping the current limiter is the quickest way to kill the MOSFET. Note the licence: it is CC BY-NC-SA, so build one for yourself, but do not sell them. If you have soldered SMD parts before, this is a spectacular weekend build.
IN THE REPO
GOOD TO KNOW
- —Repository contains schematic, PCB design, and bill of materials.
- —No 3D-printed parts — the coil support is made of PCBs (base plate and five support pieces), with Gerbers in the repo.
- —No firmware — the circuit is analog, a self-oscillating Class E driver at about 10 MHz.
- —Documentation covers theory, construction steps, and tuning procedure.
- —Licence is CC BY-NC-SA 4.0: personal and educational builds only, no commercial use, and derivatives must be shared alike.
- —Missing: a schematic walkthrough in English beyond the parts list; the tutorial is mostly photos plus step text.
Parts to buy
4 itemsFrom our check of the build. Exact quantities and part numbers are in the creator’s BOM.
Can I build this?
Build at your own risk. Projects involve tools, electronics and sometimes mains voltage — follow the creator’s safety notes.
Videos
Official demo from the creator's HaloPlasma channel showing the xenon toroid running; the step-by-step build is a photo tutorial in the repository (English, Spanish, Russian and Chinese).
More builds like this
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Start here
Navigation into the creator’s own docs — we don’t rewrite the guide, we route you to the source.
- 1.Read the theory document in the repository to understand the resonant LC circuit and plasma formation.(A short section explains glow discharge and how the roughly 10 MHz Class E oscillator makes the ring; the safety warnings come right before it.)
- 2.Buy the 80 mm xenon-filled glass bottle(Larger bulbs will not fit the coil bracket; the creator sells the matching bottle and full parts kit (AliExpress, Tindie).)
- 3.Order the PCB from the Gerbers in the hardware folder and buy the BOM components.(Standard through-hole and a few SMD parts, nothing exotic. The resonant capacitors are fixed; the only control is a 1k potentiometer. Mind the orientation of the electrolytic capacitor and the 9.1 V Zener diode.)
- 4.Wind the 4-turn coil through the PCB bracket and assemble the driver board(Mind the MOSFET orientation and heatsink; the frequency (about 10 MHz) is set by fixed capacitors.)
- 5.Power on through a current-limited 24 V supply and place the bottle on the coil(If it glows white without a ring, reposition the bottle and re-ignite a few times.)
KNOWN ISSUES
- Only the 80 mm xenon bottle fits the coil bracket — larger glass balls will not mount. Buy the matching pre-filled bottle rather than improvising one.
- Sometimes the bottle glows white without forming a ring. Adjusting the bottle position and re-igniting a few times usually fixes it.
- Most failed builds are bad solder joints — the author says 60% of problems come from poor contact. Solder carefully and check capacitor and diode orientation.
- The drive circuit and coil carry high voltage while running and can shock or burn you. Keep your hands at least 1 cm from the coil, and never hold the bottle while touching the potentiometer: static on the bottle can damage the circuit.
- It is not a lamp. The creator recommends running it for no more than two minutes at a time, because the circuit, coil and bottle heat up.
Can I use a different noble gas instead of xenon?
The project documents only xenon: the 80 mm bottle comes sealed and pre-filled with low-pressure xenon, which gives the pale purple glow. Other gases are not covered, and you cannot refill or adjust the bottle yourself.
Do I need a vacuum pump, or can I use a syringe to evacuate the sphere?
Neither. You do not evacuate anything: the project uses a sealed 80 mm glass bottle pre-filled with low-pressure xenon, sold by the creator's store.
What size sphere should I use?
80 mm. The coil bracket is designed for an 80 mm xenon-filled bottle, and larger glass balls cannot be installed.
How much power does this draw?
It runs from a 24 V supply rated 4 A or more, current-limited to 3.5 A — up to roughly 80 W, which is why the MOSFET needs a heatsink and fan. Without current limiting the MOSFET burns out easily.
Is this safe to run continuously?
No. The creator says the circuit heats up and recommends running it for no more than two minutes at a time. While it is powered, the drive circuit and coil carry high voltage, and the bottle gets hot, so treat it as live and hot. Switch it off and disconnect the power after use.
Community builds
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Discussion1
FROM THE COMPAREE TEAM
The plasma ring forms inside an 80 mm xenon bottle driven by a roughly 10 MHz Class E oscillator from a 24 V supply. Where would you put one: on a desk, in a classroom, or in a display case?
Simon Liu
Simon Liu, who sells as Diagon Alley Magic Shop and HaloPlasma, published the driver board, coil holder and a photo tutorial in four languages so hobbyists can build their own xenon plasma ring, and runs a Telegram group for builders' questions.
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DISCLAIMER
- Comparee is not the author of the projects featured here. All rights to each project belong to its creator — every page links to the original source, and we never host creators’ files.
- Information is provided without warranty and may become outdated as projects evolve. Prices are indicative bands only — always check the creator’s parts list for current costs.
- Building and operating any project is at your own responsibility. Protective equipment, safe workshop practice and compliance with local regulations are the builder’s responsibility.
CompareeTEAM2mo agoedited
Practical notes from our verification: the repository contains the Gerbers for the driver board and for the PCB coil holder and stand, a BOM, and a step-by-step tutorial (in Chinese, English, Spanish and Russian) with dozens of assembly photos covering coil winding, soldering, heatsink and fan. There is no vacuum work involved: the sphere is a specified 80 mm glass bottle that comes pre-filled with low-pressure xenon from the creator's store, and larger bulbs do not fit the bracket. The circuit is a self-oscillating Class E driver at around 10 MHz with fixed resonant capacitors and a fixed 4-turn coil, so there is no oscilloscope tuning step. Take the power seriously: it runs from a 24 V supply of at least 4 A, current-limited to about 3.5 A, and the glass gets hot. The licence is CC BY-NC-SA 4.0 and the author explicitly forbids any commercial use. There is an official demo video, and technical questions go to the project's Telegram group. Correction (4 October 2026): we re-checked this page line by line against the project's own repository, documentation and videos, and fixed errors in earlier versions.