The CV850 is a low noise RF voltage amplifying pentode, designed to operate at VHF.
The KB/D identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority and the D identifies the maker as Mullard Radio Valve Co., Mitcham.
The folded anode is stitched on one side and the sides are mainly open and so the inner structure is clearly seen. Each grid is wound at a different pitch with the suppressor grid an open helix.
The working face of the anode. The heater wire is coiled and then insulated to make the single inverted V that is inserted into the cathode.
The thin glass tube envelope is 18 mm in diameter and excluding the B7G base pins measures 37 mm tall.
References: Data-sheet & 1040. Type CV850 was first introduced in 1952. See also1952 adverts.
