A Miniature Power Supply For High Voltage Hacking

If you’re looking to experiment with plasma, you’re going to need a high voltage power supply. Usually that means something big, complex, and (naturally) expensive. But it doesn’t have to be. As [Jay Bowles] demonstrates in his latest Plasma Channel video, you can put together a low-cost power supply capable of producing up to 20,000 volts that fits in the palm of your hand. Though you should probably just put the thing down on a table when in use…

Finding the feedback coil with a multimeter.

The secret to the build is the flyback transformer. A household staple during the era of CRT televisions, these devices can still be readily found online or even salvaged from a broken TV. We’d recommend searching eBay for new old stock (NOS) transformers rather than risk getting blown through a wall while poking around in an old TV you found on the side of the road, but really it all depends on your experience level with this sort of thing.

In any event, once you have the flyback transformer in hand, the rest of the build is very simple. [Jay] demonstrates how you can determine the pinout for your transformer even if you can’t find a datasheet for it, and then proceeds to assemble the handful of ancillary parts necessary to drive it. Housed on a scrap of perfboard and mounted to a piece of plastic to keep stray objects away from the sparky bits underneath, this little power supply would be a reliable workhorse for anyone looking to start experimenting with high voltage. Perhaps an ionic lifter is in your future?

Readers with a photographic memory may recall that [Jay] used this same diminutive power supply in his recently completed water-based Marx generator.

17 thoughts on “A Miniature Power Supply For High Voltage Hacking

  1. I love this. I’ve wanted a small HV power supply in the 8 to 50KV range for a couple of small projects, and was looking at repurposing an electric fence energizer. I think something like this will work better for me.

    Also, do you have recommendations for how you would change the circuit for higher voltage output? By that I mean if you wanted to play with 100KV?

    1. Getting 100kv direct from a CRT flyback is not really feasible. Even under oil in a vacuum, 50Kv is pushing it. And most modern DC(built in diodes) flybacks aren’t happy above 20Kv and will fail by 30. I have gotten lucky with old AC flybacks, stripping the wax and potting under vacuum, but even my 5inch cored, huge secondary starts leaking Corona around 50kv. Best bet for 100kv is using an AC flybacks(from old Tube TVs, can be bought on eBay for less than $20), with a Cockroft-Walton voltage multiplier to achieve 100kv DC.

    2. Not all that convinced he’s getting 20 kV. Distinct lack of measurement gear…

      Anyhow, to accomplish exactly the same thing, just buy a plasma ball and rip the glass bit off. There’s a fly-back and associated circuit and it comes with a free wall-wart. They happily make several kV peak to peak which can be rectified or fed through a multiplier. Mileage will vary voltage wise, I’ve had from 5 kV to over 10 kV.

      Getting to 100 kV is more challenging as all the problems are harder. More leakage and less drive current. Would suggest a Van de Graaff for inexpensive fun with quite silly voltages. But if starting with a fly-back system, use a reasonably powerful and quite high frequency one followed by a Cockcroft–Walton multiplier.

      The Glassmann HV set I get to use, has a fly-back and an interchangeable (for positive and negative) Cockcroft–Walton multiplier output stage. It’s good for 125 kV at 5 mA.

    3. As we can’t edit comments – here’s a second:

      Tripped over this device:

      And some time ago purchased a 60 kV for about £60. Bargain. Dangerous, oh so hideously dangerous bargain. Especially as used it to prove a point about inexpensive circuits powering commercial x-ray equipment and made loads of radiation.

      For the curious, we needed a floating filament PSU and – 60 kV. So put a car battery in a large saucepan, sat it on polystyrene blocks and connected it to the eBay HT supply. All done inside a lead lined room though with remote power control and radiation monitoring.

    4. A friend of mine built few supplies based around flyback transformers from old soviet TV sets. These use a HV coil sealed in ceramic and an UU type ferrite core held together with two screws. He got up to 30kV with that. He later got a X-Ray head that included 60kV (IIRC) iron core transformer. Add to that a voltage doubler and an autotransformer to adjust the voltage and you get your 100kV. It would need some transformer oil for safety…

  2. Just buy a commercial HT PSU in an enclosure and use sufficiently rated HT wire.

    This PSU gets a number of things right but there are still several safety failures and to top that off he is using wire rated at 1000v or less for HT. Also HT connections should always be captive.

  3. The guys over at https://4hv.org/ have been making these, marx generators, Tesla coils, etc for years. 100Kv out of a tv fly-back is pretty close to impossible due to the insulation breakdown of the wire in the transformer. Also most modern fly-backs like the one shown have an internal Walton multiplier so then you run in to the voltage limits of the diodes and caps. As for 20Kv, most fly-backs are rated for around that anyways so it can handle it.

  4. I needed a HV PSU for an ongoing project of mine, and initially didn’t want to spend the money on a commercial unit, so I checked out a bunch of the DIY options. The cheapest I could come up with would have used a dual output (wasted spark) automotive ignition coil – even found a HaD article about it. I wanted one with dual output specifically so I could ground either of the terminals so that I could generate HV in either polarity. These can be had really cheap from junk yards at various multi-k voltages. Ultimately, I decided to splurge and bought a proper, high-quality used commercial unit for ~$160. It has switchable polarity like I wanted, and is adjustable from 100V to 30kV DC with very good voltage regulation and some other nice bits like short circuit protection and current measurement.

    1. What unit did you end up going with? I’ve been hunting for something in that price range and haven’t had a whole lot of luck (or have been looking for the wrong thing)

      1. As with so much specialty equipment, sometimes it takes a little patience to find something appropriate show up on eBay. The unit I settled on is the HP030 from Applied Kilovolts. Searching that brand probably has the most hits on eBay over any other, but be aware, they don’t all support reversible output polarity! There was another brand that I was looking at (I don’t remember the name), but the company didn’t appear to be around anymore IIRC, and finding information was kind of tough.

  5. I can’t believe I just read through this whole modestly-involved thread which had the subject matter revolving around doing rather risky/hazardous [EEEEK] projects (aka fun learning) with out a card-carrying representative of the Internet Buzzkill Saftey League doing what they do best and derailing productive discourse towards acquiring/exchanging knowledge by posting diatribes of discouragement if there’s a perceived risk or danger involved, regardless of how asnine-ly self-evident those dangers are, like in the topic discussed right here. It was just a refreshing, rare occurrence & felt compelled to say as much since it feels like I live in the era of interacting with the world as if I’m proper adult is a concept that exists entierly in a fancifully theoretical sense now. Anyway, whomever reads this: I say take lots of unnecessary risks, sastisfy all of your curiosities about the endless things in the world that can easily kill you, and make things explode with that being an end in itself if you’re not already.

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