Sensibly equivalent¶ to:
The PM4DX triode is a medium impedance design for use as a detector in TRF sets. The envelope has etched into it a 4DX and also the Mullard logo that appeared on the ORA of an aerial-coil-and earth symbol. Additionally the envelope carries a code D208.
The balloon envelope is 43 mm in diameter and, excluding the B4 base pins, is 90 mm tall.
References: 1931 datasheet & 1043. Type PM4DX was first introduced in 1928.
Absolute Maximum Operating Conditions¶
Thanks to Andy Cowley for supplying the above PDF datasheet.
Updated May 26, 2018. shape:balloon construction:pinch type:triode age:1920.1930 base:b4 heater:4.0v pins:4 pin:1.a pin:2.g1 pin:3.f pin:4.f