The Two in One has a double electrode structure (filament, control grid and anode). This sample has a chrome base cap and barium gettering and also a machine made envelope.
The original box measure 50 mm square and is some 128 mm tall. This is a later redesigned box with better information.Thanks to Joe Gruber for sending the images.The balloon envelope is 44 mm in diameter and, excluding the UV base pins, is 104 mm tall.Reference: Joe Gruber. Type Two in One was first introduced in 1919. See also 1919 adverts. |
Pin Connections
| 1 | 2 | 3 | 4 |  g1 | f | f | a |
|
|
Updated February 08, 2021.
|
|
