3) UY41=31A3 Telefunken Germany <> bottom NOS 1962 original boxes

Vfil=31V

The UY41 is a half wave rectifier from the first development of all glass valves in the mid 1940s. The envelope is shaped to replace the metal skirt and location pip of the original B8A valves. The locating device being essential as all pins are equi-spaced around the circumference of the pin circle.

The valve would be damaged if not operated with a minimum series resistance of 210 Ohms. The maximum value of reservoir capacitor should be limited to 50 µF

The thin glass tube envelope is 21 mm in diameter and, excluding the B8A base pins, is 58 mm tall.

References: Datasheet, ³⁰⁰² & ¹⁰⁴⁰. Type UY41 was first introduced in 1947.