The Catkin version of the VMS4 variable μ screened tetrode dates from 1934. It was designed for RF and IF amplification in broadcast superhet receivers.![](../pics/aaq0186a.jpg)
The screw top cap. Looking into the valve one can see that the actual copper anode is of much smaller diameter than the outer screening can.![](../pics/aaq0186b.jpg)
This M-OV valve carries the consumer Osram label.The wide metal tube envelope is 34 mm in diameter and, excluding the B5 base pins, is 107 mm tall.References: Data-sheet & 1005 Type VMS4 was first introduced in 1931. See also 1931 adverts. |