The U10 directly heated full wave rectifier has an internal coating on the upper part of the envelope. A close look shows that the valve has cathode tubes that are internally strapped to one side of the filament.

The maximum reservoir capacitor is not quoted, but at 60 mA maximum output current the U10 was clearly designed for broadcast radio reception in 1930s all mains sets. The 4.0 Volt heater is characteristic of the early 1930s British heater standard.

The classic envelope is 40 mm in diameter and, excluding the B4 base pins, is 97 mm tall.

 
Pin Connections

B4	1	2	3	4
	a(1)	f	f	a(2)

 
Absolute Maximum Operating Conditions

Rectifier	Vh	Ah	Va	mAa
	4.0	1.0	250	60

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 12 June 2007 {find valves by name}