Type UU4 is a indirectly heated full wave rectifier. The cathode is strapped to one side of the heater and so the heater has to be connected to a separate winding on the mains transformer.

The identification lettering is on the top of the dome.

Each anode is a complex pressed plate, blackened to make a better radiator.

The classic envelope is 42 mm in diameter and, excluding the B4 base pins, is 100 mm tall.

 
Pin Connections

B4	1	2	3	4
	a(1)	a(2)	h,k	h

 
Absolute Maximum Operating Conditions

Rectifier	Vh	Ah	Va	mAa
	4.0	2.2	400	120

Thanks to Frank Philipse for supplying the above datasheet

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