The SP42 is an HF pentode for use in the video output stage in early television receivers.

Thanks to Leif Ekornrxd (LA9IM) for the picture. Click here for Leif's site.

The classic envelope is 32 mm in diameter, and excluding the MO base pins is 76 mm tall.

References: Datasheet, ¹⁰⁴⁰ & ¹⁰⁴³. Type SP42 was first introduced^¶ in 1938.

 
Pin Connections

MO	1	2	3	4	5	6	7	8	tc
	h	k	a	g2	g3	m	-	h	g1

 
Absolute Maximum Operating Conditions^¶

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	gm
	4.0	0.95	200	200	-1.5	20.0	5.0	9.0

Thanks to Frank Philipse for supplying the above PDF datasheet