Sensibly equivalent¶ to:
The VT127A was made for the UK General Post Office (GPO) then state run. In 1941 with the advent of the CV register the old GPO valves were called POVT in the literature to distinguish them from the VT as used by the RAF.
The valve is a double diode with a defined heating time of 17 seconds. The prototype was the DDL4. The voltage given is 200 but the test uses 10 Volts and the commercial valve is quoted as having a maximum anode voltage of 20 Volts.
The gettering obscures the inner structure.
The balloon envelope is 30 mm in diameter, and excluding the B5 base pins is 82 mm tall.
Absolute Maximum Operating Conditions¶
Updated April 07, 2019. shape:balloon construction:pinch type:double.diode age:1930.1940 base:b5 heater:4.0v pins:5 pin:1.a(1) pin:2.a(2) pin:3.h pin:4.h pin:5.k