Phil Hobbs wrote:


Maybe Barkhausen oscillation (aka the Barkhausen-Kurtz effect). This
used to show up in old-fashioned incandescent light bulbs that were
evacuated instead of argon-filled.

according to a wikipedia article, the Barkhausen-Kurz oscillator used
triodes. So I'm still puzzled.
I'll try to make a test setup with constant current on a GDT and try
to measure the frequency of the oscillation.

Frank