Siemens & Halske
tube type OR
From the collection of the
Technical University, Delft, The Netherlands
Photo by, Adri de Keijzer
Siemens & Halske tube type OR
This is a Space Charge (two grid) tube from the early 1920 's.
From the "Taschenbuch der drahtlosen Telegraphie und Telephonie" by F. Banneitz, issued 1927.
I have the following data:
OR = Telefunken RE 87.
Oxid filament 2.5V at 1.1A .
Sp. Ch. grid 80V, Anode 220V, slope 7 to 10 mA/V, Durchgriff 4% (mu = 25).
(I suppose this is the saturation current).
This particular tube has 380 hours of operation, as indicated on the label at the socket.
The photo was made in July 2000, using a Nikon Coolpix 950 (2.1M pixel)