The CV140 is a double signal diode, commercially this was the 6AL5, the valve the UK Government CV specification was based upon.
The two valves are completely separate flat structures separated by a plate screen. This clearly shows the signal usage, where it is important to keep RF isolation.
Mullard designed these diodes for vision and sound detection.
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.
Face view of one diode.
The Mullard logo and the commercial Type designation EB91.
The thin glass tube envelope is 18 mm in diameter, and excluding the B7G base pins is 46 mm tall.
References: Data-sheet & 1040. Type CV140 was first introduced in 1946. See also1946 adverts.
