Class E Tesla Coil 10.87Mhz

On my search for the silent arc i came across a video of a German fellow coiler for a HFSSTC running at approx. 10 MHz.
This device had this arc which was able to ionize the air around the arc,
creating almost a fiery flame effect over the corona discharge.
Because of the high frequency it turned out the air didn’t get enough time to fully de-ionize hence leaving this plasma like flame.
I was intrigued by the appearance of the flame and started building right away.

This build had a relatively low amount of parts which seems as a very simple circuit at first.
But some of the values in the circuit have to be picked very carefully to get the best possible efficiency and output from the device.

Completed Class E Tesla Coil Schematic @ 10.87MH
You can share the schematic freely, provided that no commercial use is made.

As you probably noticed the circuit consists out of the following parts:
– 2x 1k 2watt resistor
– 1x 10k potentiometer
– 3x 1n5349BRL zener diode
– 1x IRFP260n
– 1x 150pF MMC (i used 4×4 Wima fkp1 150pF)
– 1x 4.5nF ext. gate capacitance
– 1x 20t RFC inductor
– 1x 4.5t Primary/Feedback Resonator
– 1x 130t Secondary Resonator

Inside view of the circuitry

On the far left side we can see the big capacitor which i initially used as DC bus capacitor.
This capacitor got excluded from the circuitry by the time i started using the class e coil for audio modulation.
at the center of the picture we see the 20 turn RFC inductor and right next to it the external gate capacitance with the IRFP260n right behind it.
On the right side of the picture we see the 4×4 MMC capacitor.

Overview of the completed coil assembly.

Here we see a overview of the completed project.
On the picture you’ll see 1 plate on each side.
They are connected to the mosfets drain and offer some capacitance for the output to push against.

For the secondary resonator i used acrylic 25mm tube which kind of was a terrible idea.
The heat of the arc and the heat due to skin effect on the particular frequency was so bad 5 minute runs was all i was able to do.
And perhaps am changing the coil form from acrylic to alumina in the future.

Normal Operation
Modified breakout point dipped in molten boro-silicate