The UY85 half wave rectifier was designed for use across the European mains, as the 100 mA heater suggests. The reservoir capacitor specified is 100 µF and the minimum effective series resistance in the circuit needed to be only 100 Ω.
The design use was in domestic broadcast receivers for the main HT rail.
The two halves of the anode are stitched together.
The ends of the anode plates are opened out to increase the radiating area. Note that the inside of the anode plate is left bright - No desire to radiate back into the cathode!
The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 58 mm tall.
References: Data-sheet & 1040. Type UY85 was first introduced in 1954. See also1954 adverts.
