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.

Large 150kV gaps proved slightly effective but with no large gains, at least not compared to the dielectric barrier method. Of which, glass as the dielectric leads straight to holes, and HTPE gets cooked, but in the end, he was able to produce a somewhat sizable amount of ammonium nitrate. The best design included two test tubes filled with baking soda and their respective electrodes. Of course, this comes with the addition of a very effective ozone generator.

While this project is very thorough, [Hyperspace Pirate] himself admits the extreme dangers of high ozone levels, even getting close enough to LD50 levels for worry throughout out his room. This goes for when playing with high voltage in general kids! At the end of the day even with potential asthma risk, this is a pretty neat project that should probably be left to [Hyperspace Pirate]. If you want to check out other projects from a distance you should look over to this 20kW microwave to cook even the most rushed meals!

Thanks to [Mahdi Naghavi] for the Tip!