Sensibly equivalent¶ to:
The E91H from Mullard is described as a dual control heptode for use in computer circuits. It is a special quality valve as denoted by the style of the designation with the figures before the type code and the gold plated pins.
The anode from the side, crowded with five grids.
The thin glass tube envelope is 17 mm in diameter, and excluding the B7G base pins is 53 mm tall.
References: Data-sheet & 3002. Type E91H was first introduced in 1957.
Absolute Maximum Operating Conditions¶
Updated February 08, 2013. shape:thin.glass.tube construction:all.glass type:heptode age:1950.1960 base:b7g heater:6.3v pins:7 pin:1.g1 pin:2.k.g5 pin:3.f pin:4.f pin:5.a pin:6.g2.g4 pin:7.g3