The PCF80 is from the era of VHF television in the 1950s and early 1960s. The valve is a triode pentode with separate cathodes, designed to function as a mixer and oscillator in the tuner front end.

See also PCC84 for the corresponding pre-amplifier valve for Band III television tuners from the mid 1950s. With the commencement of ITV in 1955 and the use of Band III for the first time in the UK, there was great demand for these valves and all the major players produced the design.

The tiny triode anode can be seen on the right of the picture.

The thin glass tube envelope is 20 mm in diameter and 48 mm tall, excluding the B9A base pins.

References: Datasheet & ¹⁰⁴⁰ Type PCF80 was first introduced^¶ in 1953.

 
Pin Connections

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

 
Absolute Maximum Operating Conditions^¶

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm
	9	0.3	170	170	-5.5	5.2	1.5	0.87M	2.1

Triode	Va	Vg	mAa
	100	-2	14

Thanks to Frank Philipse for supplying the above PDF datasheet

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