Telefunken EF12 pentode
Datecirca 1945
Inventory NumberVT5227
ClassificationVacuum Tube
Subject
Maker
Telefunken
founded 1903
Place of Origin
Dimensionstube: 4.7 × 4 cm (1 7/8 × 1 9/16 in.)
DescriptionThis is an RF pentode with eight contact pins. Known also as a "Stahlröhre." See cutaway example of an EF11: VT5228.
InscribedTube housing: "TELE/FUN/KEN; EF 12; 292; B.1b 02."
Curatorial Remarks7/19/01: Currently located SVG's desk.
Historical AttributesPeter von Thüna writes that this style of tube was designed by Telefunken to compete with RCA's Oktal metal tube and was considered an improvement. Its horizontal arrangement gave a single ended tube with less lead inductance and made the structure more rugged. This style and especially its base became universal in Germany for all but military tubes until production ended in 1945 when almost all tube manufacturers found themselves in the Russian zone of occupation. For more information on this tube see Stokes, John W. "70 Years of Radio Tubes and Valves" (New York: The Vestal Press, 1982), pp. 100-101, CHSI Lib No. 4613.
