Eric Jacobsen wrote:

On Fri, 08 Aug 2003 13:31:25 -0400, Jerry Avins wrote:

... It has been one of my enduring regrets
that I didn't ask to keep the bulb. It was probably thrown out.

Jerry

I think that one may have been intended for an embassy somewhere...

About a year later, I read about such a bulb in QST. The author believed
that Edison-effect electrons excited a self broad-band resonance in the
doubly coiled filament, sustaining oscillation by a mechanism I forget,
but that seemed reasonable at the time. Incandescent lamps are filled
with low-pressure nitrogen to avoid damage from the Edison effect, and
interaction with the gas figured in his explanation. It was that
explanation that led me to build an open-air triode. I was surprised as
anyone when that worked, and I took it as a confirming instance for the
now-forgotten explanation.

Jerry
--
Engineering is the art of making what you want from things you can get.
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