The 85A1 voltage stabiliser will strike at 125 volts and is useful for output currents of between 1 - 8 mA. The preferred operating point is 4.5 plus or minus 0.2 mA this indicates a design for a reference tube and not a direct stabiliser.

The envelope is opaque from all angles. The additional codes are date and location codes.

The base is a standard B8B but is unusual in that only three pins are present. I suspect that in practice this valve would have been held in place with a retaining clamp.

The wide glass tube envelope is 27 mm in diameter and, excluding the B8B base pins, is 62 mm tall.

 
Pin Connections

B8B	1	2	3	4	5	6	7	8
	-	a	-	k	-	-	-	k

 
Absolute Maximum Operating Conditions

Stabiliser	Va	mAa
	65	8

Thanks to Frank Philipse for supplying the above PDF datasheet

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This exhibit was last updated on 24 February 2008