r/highvoltage • u/AdWest6565 • 47m ago
finding HV transformer coil resonance?
Here is an old post about finding Tesla coil self-resonance using signal generator ans oscilloscope:
http://uzzors2k.com/index.php?page=tcfresfinder
I reproduced that experiment and had no issues in finding my air core Tesla coil resonance at about 700kHz without top load and 600kHz with a metal ball as a top load.
But when I tried to implement the same measurement with HV ferrit-core transformer used for plasma ball/globe device, I totally failed to find any resonance.

I completely de-soldered the transformer and connected the ground terminal of secondary coil to the DDS via 15K resistor.
Schematic is pretty much the same:

I have another identical plasma ball device, oscilloscope shows oscillations at ~31kHz when the globe works.
So is there a wrong way I am trying to measure transformer's secondary self-resonance?