High Voltage: Controlling A Flyback Transformer With An Arduino

If you’d like to build a Jacob’s ladder, an ignition system for a flamethrower, or for some ungodly reason you need 15 kilovolts for a prop replica or cosplay build, this one is for you. It’s an easy to build high voltage power supply that interfaces with an Arduino.

After harvesting a flyback from the power board of a CRT, [Andrew Moser] added a new primary coil to the transformer. This boosts 12 volts that can be easily controlled by an Arduino to something that will arc an inch and a half. The next step building the flyback driver. [Andrew] used a MOSFET and MOSFET driver for this circuit (although he says this guy works without the driver). After that, all that’s left to do is write some software and test it out.

Of course this comes with the boilerplate warning, “If you don’t know what you’re doing, you might die.” That being said, if you ever wanted to test out an Arduino’s resistance to EMP, this is the project for you. Check out the flyback powering a Jacob’s ladder after the break.

14 thoughts on “High Voltage: Controlling A Flyback Transformer With An Arduino

    1. WTF are you talking about? If the flyback is reversed it simply won’t build as much high voltage. The square wave fed into the flyback will probably still resonate the secondary and a small amount of current will be built in a ramp stage, due to the ferrite core. Flybacks even work with 1:1 ratios, but maybe with lower output voltage.

      Instead of creating a primary winding by hand, one can just use one of the other pins in modern flybacks. These pins, are attached to other coils…

      1. oh…another thing I forgot to mention…the windings inside work at like 125 VOLTS minimum…to make decent sparks you need more…and it’s in a single tranzistor circuit-deemed not to survive too long. I still think royer oscillators are the best.

  1. Just reading the description on his site about the pros/cons of different high voltage power supplies shows he does not know much about what he is doing. He should be using a self resonating circuit. There are many circuits out there for this.

  2. I am missing a way to control the duty cycle, because the higher the on time, the higher the output voltage. But all of this can be done with the good old 555 instead of a microcontroller.
    I think it is much easier to controll frequency and dutycycle via 2 potis, as if reprogramming a chip, for changing. Also I don´t like to have computers, laptops or other electrical sensitive devices near HV experiments, since i have blown an expensive Hioki DVM that stood mor than a meter away from my SSTC, also my computer keyboard gives out keystrokes when I have my ion generator running near it.

  3. Actually, I don’t think you need an ignition system for a flame thrower. The stuff in the tank is triethylaluminum, which burst into flame on contact with the air. You just need a little pressure to shoot it out of the tank.

    I have an arduino, but I am a chemist.

  4. I’ve already posted a ZVS driver in the forums…with that wimpy mosfet he’s got there…yeah…IRPF250/260’s are the best…
    In a self-resonating circuit, these produce massive golden-fiery-hissy arcs…not wimpy little sparks.

  5. An Arduino is quite an overkill for a flyback driver.

    As well as the complexity and extra cost, I suspect that the high voltage field may leak into the arduino and kill the delicate processor, or at least cause glitches in the output.

    A good old 555 is what I always use, and gives me LOTs of juice. Total cost for a 555 based flyback is about $1 – for the 555 – all the rest of the parts can be scrounged from the CRT.

    This is my build:


  6. His site is unfortunately not watchable by his neighbors, for some reason their internet keeps dropping..

    I’m joking – but I did actually have internet and cable issues from jokers in the area messing about with massive radio signals so it’s not advisable to have a thing like that in operation too much if you want to be sociable.

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