The VT-97 (commercially the 5W4) is a directly heated full wave rectifier with an oxide coated filament. The reservoir capacitor is given as 4 μF.
The RCA logo.
The commercial 5W4 is also present, in general the American Government used the commercial specification for procurement. Or the Government specification valve also was made as a commercial type. In the UK the majority of early CV types were made to a Government specification that differed from the commercial prototype to a greater or lesser extent.
The thin metal tube envelope is 25 mm in diameter, and excluding the IO base pins is 67 mm tall.
Reference: Data-sheet. Type VT-97 was first introduced in 1936. See also1936 adverts.
