The 20F2 screened RF pentode was designed for use in universal (ie no mains transformer) sets with a series connected heater chain. Mostly in television receivers at RF or as a sync separator.
The thin glass tube envelope is 20 mm in diameter and, excluding the B8A base pins, is 52 mm tall.
References: Datasheet, 1040 & 3002. Type 20F2 was first introduced in 1949.
Absolute Maximum Operating Conditions¶
Updated February 15, 2013. shape:thin.glass.tube construction:all.glass type:pentode age:1940.1950 base:b8a heater:200ma pins:8 pin:1.h pin:2.a pin:3.s pin:4.g3 pin:5.g2 pin:6.g1 pin:7.k pin:8.h