The CV3900 (5963) is a special quality double triode introduced in 1954 for use in computer and frequency divider circuits where the valve will spend much of its time cut off.
The centre tapped heater allows for the sections to be run in series (connect to pins 4 and 5 and run at 12.6 V) or parallel (connect pins 4 and 5 together and feed at that junction and pin 9 with 6.3 V).
The two triode sections. No electrostatic screen as this is not an RF device.
The Made in England and Brimar declaring membership of the British Radio and Valve Manufacturers' Association a cartel designed to protect UK industry from foreign imports.
The thin glass tube envelope is 20 mm in diameter, and excluding the B9A base pins is 48 mm tall.
