Sensibly equivalent¶ to:
The APP4C is a pentode audio output valve issued in 1936 with the then standard UK mains heater voltage of four volts. The mutual conductance at 10.0 mA/V is significant in that it was possible to drive the output stage directly from the detector for sets designed for local station reception.
The press release for the APP4C gives the AC/DC version as the PP36 with a 200 mA heater.
The attached PDF is taken from the leaflet that was packaged with the valve. Note the price reduction.
The dome of the envelope carries the identification. The valve was made in the UK.
The classic envelope is 49 mm in diameter, and excluding the B7 base pins is 106 mm tall.
References: Datasheet. Type APP4C was first introduced in 1936.
Absolute Maximum Operating Conditions¶
PDF scanned from an original document held by the museum
Updated August 30, 2018. shape:classic construction:pinch type:pentode age:1930.1940 base:b7 heater:4.0v pins:7 pin:1.g3 pin:2.g1 pin:3.g2 pin:4.h pin:5.h pin:6.k pin:7.a