Very High Voltage Using a Transformer to Make Lichtenberg Figures

Lichtenberg figures in wood are made through a fun, lethal process!

Lichtenberg figure is a general term for such figures made by high power electricity passing through wood, grass, glass or whatever, where the electricity can leave an impression. They look like a tree and its branches grown in hell!

Lichtenberg Figures in WoodTo make the figures on a wood:

  • Don’t use plywood like I did! a solid piece of wood does better.
  • Mix two tea spoons of baking soda and water and wet the surface of the wood liberally. Let it sit a bit so the liquid can penetrate a bit. This makes the wood conductive and electricity can pass through it.
  • Place electrodes on each side of the wood.
  • Create high voltage across the electrodes, preferably over 2000V. Remember the source has to be able to supply large amounts of power to be able to burn the wood.
  • As the wood heats up and burns your liquid dries up. It is better to wet it at the beginning and not in the middle of process though, otherwise it won’t look as good.
  • If the electrodes are too close or there is too much liquid, they could arc like you saw in the video and leave giant burn marks!

Now to make high voltage, the easiest way is to use a transformer you can scavenge from old or broken microwave ovens. Quite dangerous and exposed, so be very careful. If you don’t know your way around electronic, just don’t do it!

Transformers are in general used to change the voltage and current levels between the input and output. In an ideal transformer, the “Active” input and output power are equal. The active power is what does the actual work such as generating heat. Of course there are other factors in real life that waste power such as winding wire resistances, transformer core losses and such. So the output power drops a bit as the efficiency is not 100%. But at least at no load we have the following equation:

Transformer Equationwhere N is the number of turns and V is the voltage. Also there is another useful equation to calculate the number of turns ratio if you can measure the inductance. Since the windings are both on the same core, the following equation provides relation between number of turns (Nx) and the inductance of primary and secondary (Lx):

Relationship between Transformer Inductance and TurnsAs mentioned in the video, any inductor results in a current lag, resulting in 90 degrees phase shift in an ideal inductor as shown in the picture below. At any moment of time power is equal to voltage times current. But as you see in the following picture, in some areas the power would be positive and in others negative depending on the voltage and current direction.

Inductor Voltage and Current This means although when power is positive, the inductor pulls power from the supply, it puts the same amount of power back into the AC supply when the power is negative. So the net “Active” power consumption is zero. They call this “Reactive” power. It doesn’t do the work like generating heat.

So in every transformer there is always some amount of current running into the primary (depending on the impedance of primary and loading) even if there is no load connected to the adapter. If there is any power drawn from the transformer, the phase shift is not 90 degrees any more and becomes less. So there is more power drawn from the source than the power returned to supply.

Now all inductor windings and power line wires have some small resistance and the transformers have their core losses. This means that this amount of current would generate some heat over resistive elements and such. This is one of the reasons old style transformers are not efficient, because even if you don’t use them to power anything but keep them plugged in, they still get warm and waste power. So the sooner you switch to switch-mode wall adapters,the better!

24 thoughts on “Very High Voltage Using a Transformer to Make Lichtenberg Figures

  1. How did you open the “wall warts?” I’ve got one that is incredibly hard to open (and I would like to open it)…

  2. hi i’m an audience of yours from china.
    i’m very interested in physics.
    i think that your video is of great fun and have a great influence to education.
    BUT,DO BE CAREFUL when you do such dangerous experiences.
    i believe that the accident in “Very High Voltage Using a Transformer to Make Lichtenberg Figures” is not what you expected.when a watch the video,i feel very horrible.

  3. I am trying to get this to work, and while I could get it to work a few times it appears my neon sign transformer will not work for me due to ground fault protection… Is there anything I can do to remedy this, or will the transformer have to have no ground fault protection to work?

    • Basically, the ground protection is not essential for the functionality, it is “just” a safety item. So if you don’t care about safety, you can simply disconnect the ground protection.
      But somehow your question sounds like you are not really familiar with electricity so you better stop your experiments as this one can easily turn into a fatal one!

      BTW: I want the meter so badly!!!!

  4. Hi Mehdi.
    Which is the best physics branch like astrophysics and quantum physics. or any others.
    Which branch is required for electrical engineering

  5. I want to have that meetah(!!!) Since i would like to measure the milli-Henry of that mono-brow of yours… I’m a very big fan of all your funny video’s, it must be hard to create those funny like shortages that look quite dangerous…

  6. I think, technically, you are measuring the mutual inductance of the transformer. By taking an inductance measurement of the primary on a transformer with the 2ndary leads left open you are measuring the mutual inductance. Primary inductance could measured by shorting the 2ndary leads.

  7. Give me dah meetah!

    On a serious side, thank you for making these videos. My 4th grader is using these as ideas for her school projects and she is hooked on them. She built a simple parallel circuit of 24 LEDS, 2 AA batteries and a toggle switch and can not wait to work on other projects.

  8. Just signed up as a patreon. Love the videos! You’re the best!!! I would love to see a patreon-only (?) video that covers you demystifying how you are always accidentally blowing stuff up. some of it is forced, right? some of it may even be staged with prop pieces that you can destruct without affecting your primary apparatus? So funny, even if we know that it is on purpose. It is on purpose right? (most of the time.) You must shred a lot of stuff by arcing/shorting it! And if you choose to keep this all part of the “special sauce”, I’m sure we’ll all understand too.

    I have a transformer core from a junked sub-woofer system (all in one). weighs about 5 lbs, so fairly beefy. Inputs are 120, and there are 3 sets of outputs at 26v, 25v, and 13v. what happens when using the “outputs as inputs” to generate higher voltage? If I connected 120v power to the 13v “output winding” would then generate something like 9×120 on the original “input winding” ? what would happen with the other originally-an-output-winding of 26v-target? just asking broadly here as a curious question. I’m not going to use it like that. yes, I realize that I’d need to compute the windings to know for sure…

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