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Phil Hobbs

On 07/06/2017 08:35 AM, wrote:
On Thursday, July 6, 2017 at 3:19:34 AM UTC-4, frank wrote:
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

Not knowing Barkhausen-Kurz from Berkinstocks, I think Phil means it
has to do with the time delay. Enough gain and a time delay leads to
oscillations. (hmm just like in thermal control loops.)

George H.

No, it's a coupled plasma/surface effect. It's really cool. It peaks
down around a few tenths of a millitorr, but it's still appreciable at
higher pressures.

The light bulb thing was discovered by somebody turning on an
incandescent lamp and wiping out his reception.

I don't know if the pressure in the transient suppressor is low enough
for Barkhausen--if not, it's probably the neon bulb oscillation as
others have said.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net