The EF50 was the ubiquitous red valve for a decade. Designed by Philips in 1938 for Band I television receiver use and first released in 1939, this amplifier pentode was a general workhorse. 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.![](../pics/abz0053a.jpg)
The reverse of the aluminium can is plain.The wide glass tube envelope is 33 mm in diameter and, excluding the B9G base pins, is 62 mm tall.References: Data-sheet & 1040. Type EF50 was first introduced in 1939. See also 1939 adverts. |