Sensibly equivalent¶ to:
The PM4DX is a medium impedance triode for use as a detector. Exhibit PM4DX has the identification etched into the glass, this exhibit carries a paper band on the Bakelite base and has details printed on the dome of the envelope.
The balloon envelope is 43 mm in diameter, and excluding the B4 base pins, is 87 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