E.140 transmitter triode


This triode is is quite a historical tube. I bought it several years ago at a surplus offer, I didn't succeed so far in getting any closer information about it.

It is a French tube, made by SFR (Société Francaise de Radiodiffusion (?)), presumably at pre-World War-2 times. It has a round, oxide coated filament, fold three times, rating is 4 V, about 1 A.

Biplanar grid and plate are connected to top caps with screw fasteners, the base only supporting the filament leads. Plate seems to be made of the same type of metal than in most other radio tubes. So I assume, that this tube is not rated for very high power output, I suspect plate dissipation at about 20-30 Watts.

The two "external connections" of the plate and grid to the two remaining free base pins have a special purpose: I have an antique radio set, which uses a power triode in the final stage. Since that tube is quite burnt-out, I've tried to find a replacement and found this tube here to be suited quite well - with plate and grid connected to the base.... ;-)