M-OV Type U16 was originally introduced in the early 1930s, although this specimen has a paper label that matches that used in early post-war adverts. The U16 was intended for oscilloscope EHT supplies but was never widely used.
On the whole the Cossor type SU2150A was a better valve for oscilloscope use and was generally preferred.
The U16 was employed by EMI in its range of pre-war television receivers for the CRT EHT supply. The EHT being derived from a 5000 Volt winding on the mains transformer.
The maximum reservoir capacitor for this valve is 0.25 µF and the maximum current is limited to 2 mA.
The anode is a thin disk 30 mm in diameter and is held horizontally. The filament, also horizontal, is 'W' shaped and supported 6 mm away from the anode on stout wire supports. The paper label gives the Marconi Brand name.
seen in close-up the filament can be seen to be oxide coated ribbon and each support is a spring welded to the rods secured within the pinch. The anode has the edges bent up to add rigidity.
A closer view of the filament and flat circle of the anode above.
The top side of the anode and top cap connection.
The classic envelope is 44 mm in diameter and, excluding the B4 base pins, is 123 mm tall.
References: Data-sheet & 1040. Type U16 was first introduced in 1933.