PM3 Azide Triode

Detector and first audio triode, 4 V, 75 mA filament. Maximum anode voltage 150 V, grid bias -6 V, mu 14, ra 13 kOhms. Cost 14/- in 1931, equivalent to £109 today!

Here is a later one with a top logo and a box for a 1925/6 version.

PDF Data Sheet