7.2MHz Spiral PCB Teslacoil

This battery powered Teslacoil has etched windings on a print circuit board. It works on two 9V battery's. The resonance frequency is around 7.2MHz. It is a full bridge and the primary is also resonant. It has a turns ratio of 2:105 with 6mil tracks for the secondary.

I have been walking around with the idea for a while to make a Teslacoil with etched windings on a PCB. The big advantage is that you don't have to wind any coils and that the spacing and other conditions are always identical. You can just order the PCB and assemble the components and you're done. I think the concept would be great for a kit or something. The total power usage is about 5W, maximum arc length is about 12mm.

The main challenge was making a driver circuit with the least possible delays to allow the 7.2Mhz resonance frequency of the coil and still make it self resonant. It is easy to get it to work with a frequency generator, but running it on its own is a whole different story. One interesting fact is that it works about 2-3x better when the PCB is connected to ground in stead of leaving it floating. This makes a battery powered device rather useless if you need to connect an earth wire anyways. It doesn't have enough energy for a spontaneous breakout, but it still works pretty well.

I cheated a little on the video and used a bench power supply at 32V.

There is a newer version of this coil, see the article

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