Sensibly equivalent¶ to:
4066A 420T 42MP/Pen 7A2 7A3 A70C A70D AC2/Pen APP4B ARP10 ARP25 CV1181 CV3638 KT41 N41 NR59 OP42 PT4 Pen4VB TL44
The PenA4 is an audio pentode power output valve.
For the heater power the emission is not high and the audio output achieved is small. It is specified for single ended use, as would be found in radio receivers.
The top mica area. The copper supports for the control grid are topped with a heat radiating fin.
The classic envelope is 49 mm in diameter and, excluding the B7 base pins, is 120 mm tall.
References: Datasheet, private correspondence & 1043 Type PenA4 was first introduced in 1937.
Absolute Maximum Operating Conditions¶
Updated February 19, 2015. shape:classic construction:pinch type:pentode age:1930.1940 base:b7 heater:4.0v pins:7 pin:1.- pin:2.g1 pin:3.g2 pin:4.h pin:5.h pin:6.k pin:7.a