The VT50 is a battery triode with a bright anode box and a B4 base. The VT50 was an RAF specification hat later was renamed the CV1050. The commercial valve would be the HL2K.
The long anode ribbed for strength and the top mica fitting tightly into the reduced width envelope near the top.
The single inverted V filament passes through a mica disc before being held by the hook on the tensioning spring. The helical spring is mounted on a further mica strip.
The gripping fingers of the retaining mica and within the control grid and white oxide coated filament.
The feint etching on the glass contains much information. The Old Stores code of 10E/10945 indicating that the VT50 and the CV1050 were identical. The maker GEC and the Type designation VT50.
Moving the valve under the microscope highlights the 50.
The classic envelope is 28 mm in diameter and, excluding the B4 base pins, is 70 mm tall.
References: Private communication, 3002 & 4001. Type VT50 was first introduced in 1934. See also1934 adverts.
