The NU13 is a majestic piece of glassware. It is a half wave rectifier and the NU13 tells us that this was made for the UK Navy.

See NU13A for a later development.

The L4 base is 55 mm square, and is a substantial item. The valve serial number is 4581.

The wide glass tube envelope is 48 mm in diameter and, excluding the L4 base pins, is 158 mm tall.

Reference: Observation.

 
Pin Connections

L4	1	2	3	4
	a	f	f	-

 
Absolute Maximum Operating Conditions^¶

Rectifier	Vh	Ah	mAa
	6.0	-	120