Variable Frequency HV Source

I have been using solid state Tesla coils for high voltage static field experiments. However, their output is constrained by their resonant frequency. I need a wider, "manually sweepable", frequency range.

What are the proven design options for self-constructed circuit that would take a 10KHz to 100KHz square wave from a bench signal generator and output 10KV over that entire range?

An output amplitude variation over that range of 20-30% would be acceptable. Only a few microamps are required. Wave shape is non-critical.

I have seen lab quality equipment that does this ("HV amplifiers"), possibly with chained HV switching transistors, but I cannot find a cheap and dirty circuit to work from, if there is one.

Thanks for any suggestions.

Robert Miller

Reply to
Robert Miller
Loading thread data ...

I bet the right valve would handle that easily.


Reply to

I think you would need a variable capacitor, to tune the resonance of the primary coil. That may still not work that well over a 10:1 frequency range. Getting a typical Tesla coil to resonate at 100 KHz sounds tough, you might need to do some things to the secondary winding to cut the stray capacitance. Some kind of Pi winding, I think they call it.


Reply to
Jon Elson

How much current? Some HV transformer?

George H.

Reply to
George Herold


I don't have a proved in design, but here are some ideas that might help.

Use a winding geometry that insures that the lowest self-resonant frequency of your transformer secondary is well above the 100 kHz range. One option might be to wind your transformer secondary in a single-layer on a polycarbonate or Plexiglas tube. I'd avoid PVC since it can develop carbonized tracks in the presence of ANY corona or partial discharge activity. Multiple "basket-wound" pies of different sizes (like large RF chokes) may also work. Note that the secondary of a CRT HV flyback transformer is typically designed to self-resonate at 60 - 80 kHz which may cause excessive output voltage problems if you need to drive through this frequency range. The secondary should be wound using inverter-grade polyamide-imide magnet wire since it's tough and extremely corona-resistant. Use silicone-insulated "primary wire" for the primary winding.

You don't want to use a tuned primary circuit (as in a Dual-resonant Solid State Tesla Coil/DRSSTC). And, it may be simpler to use a sinusoidal signal generator instead of a square wave source. You may be able to drive an inexpensive high-voltage linear amplifier such as an LTC6090 to drive your HV transformer through a suitable bypass cap. Good luck... :)

Reply to
Bert Hickman

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.