This exhibit is marked on the base cap as G210 and we listed it as this since 2000. However, re-photographing it brought out previously unseen lettering.
The LG210 is a dull emitter triode for use as a detector of AF amplifier.
The electrodes are mounted at 45 degrees and the blackening on the envelope opposite the open ends of the anode box is a consequence of the Azide process for making the oxide coated filament. Tungsram called their version of valves made in this way as Barium Valves.
The top view: the filament strand can be seen held in a fold of the support. The top of the control grid winding is also visible. Note the yellow cast - not seen with the naked eye.
A closer view of the top of the anode box. The yellow is clearly lettering.
The now visible printing on the dome confirms the Type as LG210 and the filament as 2 V and the anode as 150 Volts.
Microscope image showing the filament fixing and part of the control grid.
The balloon envelope is 47 mm in diameter and, excluding the B4 base pins, is 87 mm tall.
References: Data-sheet & 1043. Type LG210 was first introduced in 1930. See also1930 adverts.
