The EF50 was the ubiquitous red valve for a decade and many Type designations exist for the UK valves. Here this Sylvania valve carries the USA Government procurement code of VT-250 as well as the usual EF50.The EF50 was designed in 1938 by Philips of Eindhoven for Band I television receiver use and first released in 1939. It was extensively used in radio and radar during WWII. One additional reason that so many existed was that they had a short life and so were changed often.
The maker's code in a square border.The wide glass tube envelope is 33 mm in diameter and, excluding the B9G base pins, is 61 mm tall.References: Data-sheet & 1040. Type VT-250 was first introduced in 1939. See also 1939 adverts. |
