The 6BQ7A is an all glass miniature VHF double triode and is internally screened.

A valve like this would be used for RF amplification, or frequency multiplication. In the latter case the valve is operated as a non liner amplifier. This causes harmonics of the signal frequency to appear in the anode current. The anode tuned circuit is then chosen to resonate at one of the harmonics, usually the second or third.

The thin glass tube envelope is 19 mm in diameter and excluding the B9A base pins the valve is 49 mm long.

 
Pin Connections

B9A	1	2	3	4	5	6	7	8	9
	a(2)	g(2)	k(2)	h	h	a(1)	g(1)	k(1)	s

 
Absolute Maximum Operating Conditions

Triode	Vh	Ah	Va	mAa	gm
	6.3	0.4	150	9	6.4

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 04 July 2007 {find valves by name}