Sensibly equivalent¶ to:
The CV303 is the UK government designation for the commercial EF22 and is an example of an all glass construction amplifier pentode. In this valve the whole envelope is encased in a screening aluminium can.
In the above picture the base can be clearly seen. The short pins are of hardened construction.
The pentode is described as of variable mu. That is that the characteristic curve is such that different amplifications are possible by varying the grid bias point. Mullard describe the EF22 as primarily intended for use in DC/AC mains operated equipment in the role of RF or IF amplifier.
The wide glass tube envelope is 28 mm diameter and excluding the B8B base pins is 65 mm tall.
References: Data-sheet & 1040.
Absolute Maximum Operating Conditions¶
Updated October 05, 2013. shape:wide.glass.tube construction:all.glass type:pentode age:1940.1950 base:b8b heater:6.3v pins:8 pin:1.g3 pin:2.s pin:3.g2 pin:4.g1 pin:5.a pin:6.k pin:7.h pin:8.h