No Acid: Open ICs With A Tesla Coil

We’ve taken ICs apart before, but if they are in an epoxy package, it requires some lab gear and a lot of safety. Typically, you’ll heat the part and use fuming nitric acid (nasty stuff) in a cavity milled into the part to remove the epoxy over the die. While [100dollarhacker] doesn’t provide much detail, he appears to have used a Tesla coil to do it — no hot acid required.

Initial results were promising but took a long time to work. In addition, the coil gets very hot, and there is a chance of flames. The next attempt used a 3D printed cone with a fan to push the plasma over the chip. The first attempt shorted something out, and so far, each attempt eventually burns out the MOSFET driver.

We are always interested in the practical uses of Tesla coils and what’s inside ICs, so this project naturally appealed to us. We hope to see more success reported on the page soon. Meanwhile, if you have a coil and an old IC lying around, try it. Maybe you’ll figure out how to make it work well and if you do, let us know.

The easiest chips to open are ceramic packages with a gold lid. Just use a hobby knife. There are less noxious chemicals you can use. If you want to use fuming nitric, be sure you know what you are doing and maybe make some yourself.

Build A Tesla Coil With Just Three Components

Tesla coils are beautiful examples of high voltage hardware, throwing sparks and teaching us about all kinds of fancy phenomena. They can also be quite intimidating to build. [William Fraser], however, has come up with a design using just three components.

It’s a simplified version of the “Slayer Exciter” design, which nominally features a transistor, resistor and LED, along with a coil, and runs on batteries. [William] learned that adding a capacitor in parallel with the batteries greatly improved performance, and allowed the removal of the LED without detriment. [William] also learned that the resistor was not necessary either, beyond starting the coil oscillating.

The actual 3-component build uses a 10 farad supercapacitor as a power source, hooked up to a 2N3904 NPN transistor and an 85-turn coil. It won’t start oscillating on its own, but when triggered by a pulse of energy from a piezo igniter, it jerks into life. The optimized design actually uses the shape of the assembled component leads to act as the primary coil. The tiny Tesla coil isn’t big and bold enough to throw big sparks, but it will light a fluorescent tube at close proximity.

If you like your Tesla coils musical, we have those too.

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Tesla Coil Makes Sodium Plasma

Looking for a neat trick to do with your Tesla coil? [The Action Lab] uses his coil to make a metal plasma — in particular, sodium. You can see the results in the video below.

To create a metal plasma, you need a metal vapor and sodium can create a vapor at a relatively low temperature, especially in a vacuum. The resulting glow is pretty to look at, but you will need a bit of lab gear to pull it off.

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Junkbox Build Keeps Tesla Coils Perfectly Varnished

Admittedly, not a lot of people have a regular need to varnish coils. It’s mainly something that Tesla coil builders and other high-voltage experimenters are concerned with. But since that group probably constitutes a not insignificant fraction of the Hackaday audience, and because there are probably more applications for this homebrew coil varnishing setup, we figured it would be a good idea to share it.

For [Mads Barnkob], coil maintenance isn’t something to take lightly. If you check out his Kaizer Power Electronics channel on YouTube, you’ll see that he has quite a collection of large, powerful Tesla coils, some of which are used for demos and shows, and others that seem to be reserved mainly for blowing stuff up. To prevent one of his coils from joining the latter group, keeping the coat of insulating varnish on the secondary coil windings in tip-top condition is essential.

The setup seen in the video below helps with that tedious chore. Built entirely from scraps and junk bin parts, the low-speed, low-precision lathe can be set up to accommodate coils of all sizes. In use, the lathe turns the coil very slowly, allowing [Mads] to apply an even coat of varnish over the coil surface, and to keep it from sagging while it dries.

[Mads]’ setup is probably not great for coil winding as it is, but for coil maintenance, it’s just the thing. If your needs are more along the lines of a coil winder, we’ve got a fully automated winder that might work for you.

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High Tech Pancake Tesla Coil Brings The Lightning

For several years now we’ve been following [Jay Bowles] as he brings high-voltage down to Earth on his Plasma Channel YouTube channel. From spark gaps made of bits of copper pipe to automotive ignition coils driven by the stalwart 555 timer, he’s got a real knack for keeping his builds affordable and approachable. But once in a while you’ve got to step out of your comfort zone, and although the dedicated DIY’er could still replicate the solid state “pancake” Tesla coil he documents in his latest video, we’d say this one is better left for the professionals.

The story starts about nine months ago, when [Jay] was approached by fellow YouTuber [LabCoatz] to collaborate on a PCB design for a solid state Tesla coil (SSTC). Rather than a traditional spark gap, a SSTC uses insulated-gate bipolar transistors (IGBTs) triggered by an oscillator, which is not only more efficient but allows for fine control of the primary coil. The idea was to develop an AC-powered coil that was compact, easy to repair, and could be controlled with just a couple dials on the front panel. The device would also make use of an antenna feedback system that would pick up the resonant frequency of the secondary coil and automatically adjust the IGBT drive to match.

Being considerably more complex than many of the previous builds featured on Plasma Channel, it took some time to work out all the kinks. In fact, the majority of the video is [Jay] walking the viewer through the various failure modes that he ran into while developing the SSTC. Even for somebody with his experience in high-voltage, there were a number of headscratchers that had to be solved.

For example, the first version of the design used metal bolts to attach the primary and secondary coils, until he realized that was leading to capacitive coupling and replaced them with acrylic blocks instead. If his previous videos surprised you by showing how easy it could be to experiment with high-voltages, this one is a reminder that it’s not always so simple.

But in the end [Jay] does get everything sorted out, and the results are nothing short of spectacular. Even on the lower power levels it throws some impressive sparks, but when cranked up to max, it offers some of the most impressive visuals we’ve seen so far from Plasma Channel. It was a lot of work, but it certainly wasn’t wasted effort.

Fascinated by the results, but not quite ready to jump into the deep end? This affordable and easy to build high-voltage generator featured on Plasma Channel back in 2020 is a great way to get started. If you still need more inspiration, check out the fantastic presentation [Jay] gave during the 2021 Remoticon.

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A Builders Guide For The Perfect Solid-State Tesla Coil

[Zach Armstrong] presents for your viewing pleasure a simple guide to building a solid-state Tesla coil. The design is based around a self-resonant setup using the UCC2742x gate driver IC, which is used in a transformer-coupled full-wave configuration for delivering maximum power from the line input. The self-resonant bit is implemented by using a small antenna nearby the coil to pick up the EM field, and by suitably clamping and squaring it up, it is fed back into the gate driver to close the feedback loop. Such a setup within reason allows the circuit to oscillate with a wide range of Tesla coil designs, and track any small changes, minimizing the need for fiddly manual tuning that is the usual path you follow building these things.

Since the primary is driven with IGBTs, bigger is better. If the coil is too small, the resonant frequency would surpass the recommended 400 kHz, which could damage the IGBTs since they can’t switch much faster with the relatively large currents needed. An important part of designing Tesla coil driver circuits is matching the primary coil to the driver. You could do worse than checkout JavaTC to help with the calculations, as this is an area of the design where mistakes often result in destructive failure. The secondary coil design is simpler, where a little experimentation is needed to get the appropriate degree of coil coupling. Too much coupling is unhelpful, as you’ll just get breakdown between the two sides. Too little coupling and efficiency is compromised. This is why you often see a Tesla coil with a sizeable gap between the primary and secondary coils. There is a science to this magic!

Pretty Lithium Carbonate plasma

A 555 timer wired to produce adjustable pulses feeds into the driver enable to allow easily changing the discharge properties. This enables it to produce discharges that look a bit like a Van De Graaff discharge at one extreme, and produce some lovely plasma ‘fire’ at the other.

We’ve covered Tesla coils from many angles over the years, recently this plasma tweeter made sweet sounds, and somehow we missed an insanely dangerous Tesla build by [StyroPyro] just checkout that rotary spark gap – from a distance.

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Is It A Plasma Tweeter Or A Singing Tesla Coil?

When our ears resolve spatial information, we do so at the higher treble frequencies rather than the bass. Thus when setting up your home cinema you can put the subwoofer almost anywhere, but the main speakers have to project a good image. The theoretical perfect tweeter for spatial audio is a zero mass point source, something that a traditional speaker doesn’t quite achieve, but to which audio engineers have come much closer with the plasma tweeter. This produces sound by modulating a small ball of plasma produced through high-voltage discharge, and it’s this effect that [mircemk] has recreated with his HF plasma tweeter.

A look at the circuit diagram and construction will probably elicit the response from most of you that it looks a lot like a Tesla coil, and in fact that’s exactly what it is without the usual large capacitor “hat” on top. This arrangement has been used for commercial plasma tweeters using both tubes and semiconductors, and differs somewhat from the singing Tesla coils you may have seen giving live performances in that it’s designed to maintain a consistent small volume of discharge rather than a spectacular lightning show to thrill an audience.

You can see it in operation in the video below the break, and it’s obvious that this is more of a benchtop demonstration than a final product with RF shielding, It’s not the most efficient of devices either, but given that audiophiles will stop at nothing in their pursuit of listening quality, we’d guess that’s a small price to pay. Efficiency can be improved with a flyback design, but for the ultimate in showing off how about a ring magnet to create the illusion of a plasma sheet?

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