In article WL5Pi.15410$Cd7.9085@trnddc03,
"Paul P" REMOVE paul @ REMOVE ppinyot . REMOVEcom wrote:

"ian field" wrote in message
...

"Brenda Ann" wrote in message
...

"Peter Dettmann" wrote in message
...
On Tue, 09 Oct 2007 15:07:36 -0500, Raymond Koonce
wrote:

Some photos of an unusual tube I got in a box full. It appears to be a
triode. The only numerical marking I can find indicates a Type 488. I
can't find any information on the usual spots on the web. I made a shot
from the front showing the mesh plate structure and a shot from the
top. I tested it in my tester as a 26 but with 6.3V on the filament and
it tested well in the "Good" zone. Testing as a 45 @ 6.3V on the
filament increased the purple glow and it still tested in the "Good"
zone. Does anybody know what this tube is?

Raymond

I assume that testing did not involve anything except emission, so
Alan may be right that it may be a diode.
But it seems from the photo that there may be a grid there?
Certainly it is gassy, so not really useable.

Peter Dettmann

Voltage regulator, maybe?

Thyratron?

formerly used at ALCOA for the electric furnaces....... ;~)

Also commonly used in vacuum tube era modulation monitors for AM
broadcast stations.


Regards,

John Byrns

--
Surf my web pages at, http://fmamradios.com/