When you think of neon, you might think of neon signs or the tenth element, a noble gas. But there was a time when neon bulbs like the venerable NE-2 were the 555 of their day, with a seemingly endless number of clever circuits. What made this little device so versatile? And why do we see so few of them today?
Neon’s brilliant glow was noted when William Ramsay and Morris Travers discovered it in 1898. It would be 1910 before a practical lighting device using neon appeared. It was 1915 when the developer, Georges Claude, of Air Liquide fame, received a patent on the unique electrodes suitable for lighting and, thus, had a monopoly on the technology he sold through his company Claude Neon Lights.
However, Daniel Moore in 1917 developed a different kind of neon bulb while working for General Electric. These bulbs used coronal discharge to produce a red glow or, with argon, a blue glow. This was different enough to earn another patent, and neon bulbs found use primarily as indicator lamps before the advent of the LED. However, it would also find many other uses.
If you’re hunting for a bench power supply, you’ll quickly notice options dry up above 48 V or so, and you definitely won’t find a 330 kV supply on the shelf at your local electronics shop. But with just a few parts, [Mircemk] has crafted a high-voltage source from a modified PC power supply that delivers electrifying results.
The sparks arcing over a foot of thin air are a dead giveaway, but let’s be clear: this project is not for beginners. High voltage — defined as around 1,000 V and up, with this project hitting 350 times that — carries risks of severe injury or death. Only tackle it if you fully understand the dangers and take precautions like proper insulation and never working alone.
This project showcases a Cockcroft-Walton voltage multiplier, a clever setup using diodes and capacitors to step up voltage. The capacitors charge and discharge in an alternating pattern, doubling the voltage after each diode pair. [Mircemk] uses 3 mm thick Plexiglas as an insulator, providing both structure and electrical isolation for the diode-capacitor cascade.
To achieve the 330,000 V output, [Mircemk] starts by modifying a standard PC ATX power supply, removing the Schottky diodes from the secondary winding’s output to produce a roughly 15 V square wave. This feeds into another transformer, boosting the voltage before it enters the Cockcroft-Walton multiplier. At first glance, the multiplier’s sides look identical, but their opposite polarities create a massive potential difference across the spark gap.
[Mircemk]’s benchtop exploration into high-voltage territory is a shocking success. If this project lights up your curiosity, dive into our other high-voltage adventures, like DIY Tesla coils or plasma speakers, for more electrifying inspiration.
X-ray crystallography, like mass spectroscopy and nuclear spectroscopy, is an extremely useful material characterization technique that is unfortunately hard for amateurs to perform. The physical operation isn’t too complicated, however, and as [Farben-X] shows, it’s entirely possible to build an X-ray diffractometer if you’re willing to deal with high voltages, ancient X-ray tubes, and soft X-rays.
[Farben-X] based his diffractometer around an old Soviet BSV-29 structural analysis X-ray tube, which emits X-rays through four beryllium windows. Two ZVS drivers power the tube: one to drive the electron gun’s filament, and one to feed a flyback transformer and Cockroft-Walton voltage multiplier which generate a potential across the tube. The most important part of the imaging system is the X-ray collimator, which [Farben-X] made out of a lead disk with a copper tube mounted in it. A 3D printer nozzle screws into each end of the tube, creating a very narrow path for X-rays, and thus a thin, mostly collimated beam.
To get good diffraction patterns from a crystal, it needed to be a single crystal, and to actually let the X-ray beam pass through, it needed to be a thin crystal. For this, [Farben-X] selected a sodium chloride crystal, a menthol crystal, and a thin sheet of mica. To grow large salt crystals, he used solvent vapor diffusion, which slowly dissolves a suitable solvent vapor in a salt solution, which decreases the salt’s solubility, leading to very slow, fine crystal growth. Afterwards, he redissolved portions of the resulting crystal to make it thinner.
The diffraction pattern generated by a sodium chloride crystal.
For the actual experiment, [Farben-X] passed the X-ray beam through the crystals, then recorded the diffraction patterns formed on a slide of X-ray sensitive film. This created a pattern of dots around the central beam, indicating diffracted beams. The mathematics for reverse-engineering the crystal structure from this is rather complicated, and [Farben-X] hadn’t gotten to it yet, but it should be possible.
We would recommend a great deal of caution to anyone considering replicating this – a few clips of X-rays inducing flashes in the camera sensor made us particularly concerned – but we do have to admire any hack that coaxed such impressive results out of such a rudimentary setup. If you’re interested in further reading, we’ve covered the basics of X-ray crystallography before. We’ve also seen a few X-ray machines.
Everyone loves to play with electricity and plasma, and [Hyperspace Pirate] is no exception. Inspired by a couple of 40×20 N52 neodymium magnets he had kicking around, he decided to put together a hand-cranked generator and use it to generate plasma with. Because that’s the kind of fun afternoon projects that enrich our lives, and who doesn’t want some Premium Fire™ to enrich their lives?
The generator itself is mostly 3D printed, with the magnets producing current in eight copper coils as they spin past. Courtesy of the 4.5:1 gear on the crank side, it actually spins at over 1,000 RPM with fairly low effort when unloaded, albeit due to the omission of iron cores in the coils. This due to otherwise the very strong magnets likely cogging the generator to the point where starting to turn it by hand would become practically impossible.
Despite this, the generator produces over a kilovolt with the 14,700 turns of 38 AWG copper wire, which is enough for the voltage multiplier and electrodes in the vacuum chamber, which were laid out as follows:
Circuit for the plasma-generating circuit with a vacuum chamber & hand-cranked generator. (Credit: Hyperspace Pirate, YouTube)
Some of our esteemed readers may be reminded of arc lighters which are all the rage these days, and this is basically the hand-cranked, up-scaled version of that. Aside from the benefits of having a portable super-arc lighter that doesn’t require batteries, the generator part could be useful in general for survival situations. Outside of a vacuum chamber the voltage required to ionize the air becomes higher, but since you generally don’t need a multi-centimeter arc to ignite some tinder, this contraption should be more than sufficient to light things on fire, as well as any stray neon signs you may come across.
Fiber lasers aren’t nearly as common as their diode and CO2 cousins, but if you’re lucky enough to have one in your garage or local makerspace, this technique for depositing thin films of metals in [Breaking Taps] video, embedded below, might be worth checking out.
It’s a very simple hack: a metal shim or foil is sandwiched between two pieces of glass, and the laser is focused on the metal. Etching the foil blasts off enough metal to deposit a thin film of it onto the glass. From electron microscopy, [Breaking Taps] reveals that what’s happening is that microscopic molten metal droplets are splashing up to the ̶m̶e̶t̶a̶l̶ glass, rather than this being any kind of plasma process like sputtering. He found this technique worked best with silver of all the materials tested, and there were a few. While copper worked, it was not terribly conductive — he suggests electroplating a thicker layer onto the (probably rather oxidized) copper before trying to solder, but demonstrates soldering to it regardless, which seems to work.
This might be a neat way to make artistic glass-substrate PCBs. More testing will be needed to see if this would be worth the effort over just gluing copper foil to glass, as has been done before. [Breaking Taps] suspects, and we agree, that his process would work better under an inert atmosphere, and we’d like to see it tried.
One thing to note is that, regardless of atmosphere, alloys are a bit iffy with this technique, as the ‘blast little drops off’ process can cause them to demix on the glass surface. He also reasons that ‘printing’ a large area of metal onto the glass, and then etching it off would be a more reliable technique than trying to deposit complex patterns directly to the glass in one go. Either way, though, it’s worth a try if you have a fiber laser.
It might be too soon to consider the innards of the old CRT monitor at the back of your closet to be something worth putting on display in your home or workshop. For that curio cabinet-worthy appeal, you need to look a bit further back. Say, about 150 years. Yes, that’ll do. A Crookes tube, the original electron beam-forming vacuum tube of glass, invented by Sir William Crookes et al. in the late 19th century, is what you need.
And a Crookes tube is what [Markus Bindhammer] found on AliExpress one day. He felt that piece of historic lab equipment was asking to be put on display in proper fashion. So he set to work crafting a wooden stand for it out of a repurposed candlestick, a nice piece of scrap oak, and some brass feet giving it that antique mad-scientist feel.
After connecting a high voltage generator and switch, the Crookes tube should have been all set, but nothing happened when it was powered up. It turned out that a capacitance issue was preventing the tube from springing to life. Wrapping the cathode end of the tube in aluminum foil, [Markus] formed what is effectively a Leyden jar, and that was the trick that kicked things into action.
As of this writing, there are no longer any Crookes tubes that we could find on AliExpress, so you’ll have to look elsewhere if you’re interested in showing off your own 19th century electron-streaming experiment. Check out the Crookes Radiometer for some more of Sir Williams Crookes’s science inside blown glass.
Don’t you hate it when making your DIY X-ray machine you make an uncomfortable amount of ozone gas? No? Well [Hyperspace Pirate] did, which made him come up with an interesting idea. While creating a high voltage supply for his very own X-ray machine, the high voltage corona discharge produced a very large amount of ozone. However, normally ozone is produced using lower voltage, smaller gaps, and large surface areas. Naturally, this led [Hyperspace Pirate] to investigate if a higher voltage method is effective at producing ozone.
Using a custom 150kV converter, [Hyperspace Pirate] was able to test the large gap method compared to the lower voltage method (dielectric barrier discharge). An ammonia reaction with the ozone allowed our space buccaneer to test which method was able to produce more ozone, as well as some variations of the designs.
