The U19 is a half wave high voltage vacuum rectifier. The U19 was designed to have an effective series resistance of 600 Ohms and to feed a reservoir capacitor of not more than 4 µF.
This exhibit, made by M-OV, is branded GEC which was the brand for professional sales. The U19 also made by M-OV has the identification in their characteristic lozenge shape.
This exhibit is ruggedly constructed with ceramic supports and insulators. The anode is carbonised to aid in radiating away the heat generated in use by the intense electron bombardment. The envelope also carries the CV187 marking that indicates direct equivalence.
Seen from the top: the ceramic insulator has mica wings to ensure a tight fit to the envelope. The filament tension springs have the filaments passing down their centres. The copper wire connecta the anode to the top cap.
The top components side view.
The lower ceramic insulator and electrode support. The flat anode flanges can also be seen as well as the rounded anode cavity.
The working anode space is in the centre with the side flanges seen face on.
The wide glass tube envelope is 51 mm in diameter and excluding the B4 base pins it is 165 mm tall.
Reference: Data-sheet. Type U19 was first introduced in 1947.