ID:
2068
Maker's Name:
Telegraphie Militaire
Where made:
France
circa 1916
First World War era triode valve used in military radio receivers.
The valve has a spherical glass envelope and a 4-pin crucifix base with birfurcated brass pins. The base has a lacquered brass skirt.
The electrodes have a horizontal coaxial structure, with a cylindrical anode enclosing a helical grid and straight tungsten filament.
The filament ran on 4V at 0.75A. The TM was one of the first valves with a hard vacuum.
