Fun With A Hydrogen Thyratron

March 6, 2019 by Dan Maloney 20 Comments

There’s something oddly menacing about some vacuum tubes. The glass, the glowing filaments, the strange metal grids and wires suspended within – all those lead to a mysterious sci-fi look and the feeling that strange things are happening in there.

Add in a little high voltage and a tube that makes its own hydrogen, and you’ve got something extra scary. This hydrogen thyratron ended up being just the thing for [Kerry Wong]’s high-voltage, high-current experiments. One would normally turn to the solid-state version of the thyratron, the silicon controlled rectifier (SCR), to switch such voltages. But the devices needed to handle the 30 amps [Kerry] had in mind were exorbitant, and when the IGBTs he used as a substitute proved a little too fragile he turned to the Russian surplus market for help. There he found a TGI1-50/5 hydrogen thyratron, a tube that has a small hydrogen gas generator inside – thyratrons are actually gas-filled rather than vacuum tubes and switch heavy currents through plasma conduction. [Kerry] set up a demo circuit with a small RC network to provide the fast switching pulse preferred by the thyratron, and proceeded to run 3500 volts through a couple of 1/4-W resistors with predictable results. The video below shows the fireworks.

Can’t get enough of the thyratron’s lovely purple glow? We’ve seen it before on this beautiful old switch-mode power supply. The versatile tubes also helped rebuild the first vocal encryption system.

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X-Rays And High Voltage Hack Chat

February 18, 2019 by Dan Maloney 16 Comments

Join us on Wednesday at noon Pacific time for the X-rays and high-voltage Hack Chat!

Fran Piernas likes to push the envelope a bit with projects that others might shy away from. A quick glance at his Hackaday.io profile reveals a few of the exciting projects he’s been working on recently, including a DIY X-ray machine and the high-voltage driver needed to run it. Not only that, he’s recently taken his home-brew X-ray rig to the next level – a computed tomography (CT) scanner. His YouTube channel also has some exciting stuff using potentially lethal voltages and ionizing radiation.

Please join us for this Hack Chat, in which we’ll cover:

How one safely works with high voltage and ionizing radiation;
Sourcing uncommon components like X-ray tubes;
How Fran decided to start playing at the edge of the danger zone; and
What sort of experiments he has in mind for the future.

You are, of course, encouraged to add your own questions to the discussion. You can do that by leaving a comment on the X-rays and high-voltage Hack Chat and we’ll put that in the queue for the Hack Chat discussion.

Our Hack Chats are live community events on the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, February 20, at noon, Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

Microwave Parts Become Quick And Nasty Jacob’s Ladder

February 2, 2019 by Lewin Day 20 Comments

The Jacob’s Ladder is an electrical device named after a biblical “ladder to Heaven”, consisting of a pair of vertically oriented conductors that spread apart vertically. These conductors are charged with high voltage, which creates the repeatedly climbing arc we’ve all come to know and love from science fiction movies of yesteryear.

[LOOK MUM NO COMPUTER] was on a scavenger hunt for electronic junk, and came across a microwave in a skip that was begging to be hacked. After kicking around a few ideas, it was decided that the microwave would donate its high voltage transformer to create a Jacob’s ladder. The transformer is first bolted down to a piece of wood, and creates some sparks on the bench when shorted. The output is then wired to a pair of copper pipes to create the classic effect.

Unfortunately, the device isn’t self starting, requiring the electrodes to be temporarily short circuited to generate the initial arc. We suspect that increasing the voltage may help things somewhat, either with another transformer in series or with a voltage multiplier.

It goes without saying that high voltage projects do bring certain risks to life and limb that should not be overlooked. If you’ve still got a thirst for danger, check out this home built X-ray machine. Video after the break.

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Ambitious Homebrew X-Ray Machine Reveals What Lies Within

December 24, 2018 by Dan Maloney 31 Comments

We’re not quite sure what to say about this DIY X-ray machine. On the one hand, it’s a really impressive build, with incredible planning and a lot of attention to detail. On the other hand, it’s a device capable of emitting dangerous doses of ionizing radiation.

In the end, we’ll leave judgment on the pros and cons of [Fran Piernas]’ creation to others. But let’s just say it’s probably a good thing that a detailed build log for this project was not provided. Still, the build video below gives us the gist of what must have taken an awfully long time and a fair amount of cash to pull off. The business end is a dental X-ray tube of the fixed anode variety. We’ve covered the anatomy and physiology of these tubes previously if you need a primer, but basically, they use a high voltage to accelerate electrons into a tungsten target to produce X-rays. The driver for the high voltage supply, which is the subject of another project, is connected to a custom-wound transformer to get up to 150V, and then to a voltage multiplier for the final boost to 65 kV. The tube and the voltage multiplier are sealed in a separate, oil-filled enclosure for cooling, wisely lined with lead.

The entire machine is controlled over a USB port. An intensifying screen converts the X-rays to light, and the images of various objects are quite clear. We’re especially impressed by the fluoroscopic images of a laptop while its hard drive is seeking, but less so with the image of a hand, presumably [Fran]’s; similar images were something that [Wilhelm Röntgen] himself would come to regret.

Safety considerations aside, this is an incredibly ambitious build that nobody else should try. Not that it hasn’t been done before, but it still requires a lot of care to do this safely.

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Mini Van De Graaff Is A Shocking Desk Toy

December 10, 2018 by Tom Nardi 21 Comments

The Van De Graff generator is a device capable of generating potentially millions of volts of electricity which you can build in an afternoon, probably from parts you’ve got in the junk bin. This is not a fact that’s escaped the notice of hackers for decades, and accordingly we’ve seen several Van De Graaff builds over the years. So has high voltage hacker [Jay Bowles], but he still thought he could bring something new to the table.

The focus of his latest build was to not only produce one of the most polished and professional versions of this venerable piece of high voltage equipment, but also make it accessible for others by keeping the design simple and affordable. The final result is a 40,000 volt Van De Graaff generator that’s powered by two AA batteries and can fit in the palm of your hand.

Put simply, a Van De Graaff generator creates static electricity from the friction of two metal combs rubbing against a moving belt, which is known as the triboelectric effect. The belt is stretched between the two combs and passes through an insulated tube, which serves to “pump” electrons from one side to the other. The end result is that a massive charge builds up on the positive side of the Van De Graaff generator, which is all too willing to send a spark firing off towards whatever negatively charged object gets close enough.

The video after the break guides viewers through the process of turning this principle into a practical device, illustrating how remarkably simple it really is. A common hobby motor is used to get the belt going, in this case just a wide rubber band, and the rest of the components are easily sourced or fabricated. Even for what’s arguably the most intricate element of the build, the combs themselves, [Jay] uses nothing more exotic than aluminum foil tape and a piece of stranded wire splayed out.

Combined with the acrylic base and the purpose-made metal sphere (rather than using a soda can or other upcycled object), the final result not only generates healthy sparks but looks good doing it. Though if the final fit and finish isn’t important, you could always build one out of stuff you found in the trash.

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High Voltage Measurement Is Shockingly Safe

November 17, 2018 by Bryan Cockfield 9 Comments

With the right equipment and training, it’s possible to safely work on energized power lines in the 500 kV range with bare hands. Most of us, though, don’t have the right equipment or training, and should take great care when working with any appreciable amount of voltage. If you want to safely measure even the voltages of the wiring in your house there’s still substantial danger, and you’ll want to take some precautions like using isolated amplifiers.

While there are other safe methods for measuring line voltage or protecting your oscilloscope, [Jason]’s isolated amplifier method uses high voltage capacitors to achieve isolation. The input is then digitized, sent across the capacitors, and then converted back to an analog signal on the other side. This project makes use of a chip from TI to provide the isolation, and [Jason] was able to build it on a perfboard while making many design considerations to ensure it’s as safe as possible, like encasing high voltage sections in epoxy and properly fusing the circuit.

[Jason] also discusses the limitations of this method of isolation on his site, and goes into a lot of technical details about the circuit as well. It probably wouldn’t get a UL certification, but the circuit performs well and even caught a local voltage sag while he was measuring the local power grid. If this method doesn’t meet all of your isolation needs, though, there are a lot of other ways to go about solving the problem.

Pint-sized Jacob’s Ladder Packs 10,000 Volts In A Pickle Jar

November 5, 2018 by Brian Boucheron 12 Comments

File this one away for your mad scientist costume next Halloween: [bitluni]’s Pocket Jacob’s Ladder is the perfect high voltage accessory for those folks with five dollars in parts, a 3D printer, and very big pockets.

[bitluni]’s video shows you all the parts you’ll need and guides you through the very simple build process. For parts, you’ll require a cheap and readily-available high-voltage transformer, a battery holder, some silver wire for the conductors, and a few other minor bits like solder and a power switch.

Once the electronics are soldered together, they’re stuffed inside a 3d printed case that [bitluni] designed with FreeCAD. The FreeCAD and STL files are all available on Thingiverse. We’re not sure what type of jar [bitluni] used to enclose the electrodes. If your jar isn’t a match, you’ll have to get familiar with FreeCAD or start from scratch with your favorite CAD package.

Either way, we enjoy the slight nod toward electrical safety and the reuse of household objects for project enclosures.

If you’re interested in a Jacob’s Ladder with significantly higher voltage we’ve got you covered, or we’ve also written about another tiny portable Jacob’s Ladder.

The full video is embedded after the break.

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