The 6R7 double diode triode was designed for radio receiver use. In the classic superhet broadcast receiver such a valve would provide signal and AGC rectification, followed by the first audio amplification.

The control grid of the triode was taken to the top cap. The cap is fitted to an insulating disc that is clamped to the envelope by rolling over the top of the metal tube.

The thin metal tube envelope is 25 mm in diameter, and excluding the IO base pins, is 63 mm tall.

 
Pin Connections

IO	1	2	3	4	5	6	7	8	tc
	m	h	a	ad(2)	ad(1)	-	h	k	g1

 
Absolute Maximum Operating Conditions

Triode	Vh	Ah	Va	Vg	mAa	ra	gm
	6.3	0.3	250	-9	9.5	8,500	1.9

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 19 April 2008 {find valves by name}