Sensibly equivalent¶ to:
RAF Valve Receiving VR55 has the commercial equivalent of the EBC33, a double diode triode with a common cathode. The design dates from the late 1930s (1937-1940).
Typically double diode triode valves would be used in superhet receivers at the end of the IF amplification chain. One diode would produce the AGC voltage and the other would be used as the AM signal demodulator feeding into the triode as a first audio amplifier.
The reverse carries the crown and letters A and M for the UK Air Ministry, referred to in WWII as standing for Arthur Mitchell.
The classic envelope is 30 mm in diameter and, excluding the IO base pins, is 87 mm tall.
References: Data-sheet, 1040 & 1043. Type VR55 was first introduced in 1938. See also 1938 adverts.
Absolute Maximum Operating Conditions¶
Updated January 06, 2022.