R J Carpenter wrote:

"Rob Judd" wrote in message
...

Open-air triode?? Do tell, you have me fascinated...

IIRC, field effect triodes {FETs} were made about the same time as the first
vacuum tubes, but they didn't work well enough, given materials technology
of the day.

I thought that FETs dated to the early 30s. De Forest's "audion" was
invented in 1903 and made long-distance telephony practical by 1913.

Jerry

P.S. to Rick: That was before my time.
--
Engineering is the art of making what you want from things you can get.
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