The 6F26 is a VHF varible-mu pentode where the stage gain is controlled by the negative bias applied to the control grid. At the time this design was developed television receivers operated on Band I at about 50 MHz and from 1955 also on Band III at around 175 MHz. The EF183, released in the 1960s, overtook its performance.

When Band Iv and Band V UHF television entered service in the early to mid 1960's the front end required specialised triodes to operate at 400 - 850 MHz.

The reverse side of the circular anode and the made in England by a BVA member.

The compound pins with the red section having the same expansion co-efficient as the hard glass used for the base.

The thin glass tube envelope is 20 mm in diameter and, excluding the B9A base pins, is 59 mm tall.

 
Pin Connections

B9A	1	2	3	4	5	6	7	8	9
	k	g1	k	h	h	s	a	g2	g3

 
Absolute Maximum Operating Conditions

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm
	6.3	0.3	250	100	-2.0	10.0	2.5	0.5M	6.0

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 10 May 2009