The VU39 is a pre-CV register name for a full wave rectifier used by the RAF. This valve when used by the UK Government was labelled VU39 for the RAF or NU17 for the Navy or AU3A for the Army or even the POVT142 when purchased by the GPO. The rationalisation of the 1941 CV (Common Valve) register called the specification the CV1039.
The specification was based on rectifiers from the major manufacturers:- MU12/14 from M-OV, UU5 from Mazda, IW4 from Mullard etc.
The side flanges are perforated and the anode is ribbed for strength.
The dome. The valve is indirectly heated with both heaters run in parallel. A central rod passes to the top mica and tapes connect it to the two cathode tubes. One side of the heater is connected to the cathode.
The classic envelope is 45 mm in diameter and excluding the B4 base pins, is 104 mm tall.
