Full-Wave Rectifier
The 5R4WGB / 5R4WGA Vacuum tube is a glass octal type used in the
power supplies of radio equipment having high DC
requirements. It requires an octal socket. Vertical tube mounting is
preferred but horizontal mounting is permissible if pins
1 and 4 are in a vertical plane.
The W code indicates specail factory processing OR testing for military applications.
There is NO functional or performance difference between W and non-W.
The G code refers to the shape of the glass envelope.
The 5R4WGB was a ruggedized version of the 5R4GB specifically designed for use in military B52 bomber
aircraft. It has an unusual shape, thick glass, and a molded base that extends partially up the sides of
the glass. This shape has given it the nickname "potato masher". Because of its shape the 5R4WGB may not
fit in applications designed for the 5R4GA or 5R4GB. The 5R4GB is an upgraded spec version of the 5R4GA.
I believe the spec change is the PIV and peak plate current rating, but I am not sure. Verify before
substituting.
All of these tubes are dual rectifier diodes with a common cathode. and all have similar plate
current ratings.
The 5R4 types are particularly sensitive to the value of the input filter cap in 50 or 60 Hz applications. I have
seen them spark out on start up even with the suggested cap value.
The A code usually means that the tube is a revised design introduced sometime after the tube had been in
production - usually to address some problem, or to make the tube suitable for a wider range of applications.
However in this case it principally means a different shape glass envelope - smaller with parallel sides instead of
a shoulder bulge.
Electrical Data:
Heater Voltage ................................ 5.0 V
Heater Current ................................ 2.0 A
Preferred Substitutes: ..............5R4GA, 5R4BB, 5R4WGA, 5R4WGB.