The EH90 is an indirectly heated heptode designed for television service in dual standard sets as an FM demodulator for 6 MHz inter-carrier sound.

See EH90 for full details.

The side view of the anode shows the wire grids. The rods visible either side of the centre above the top mica are the g3 supports.

The thin glass tube envelope is 18 mm in diameter, and excluding the B7G base pins is 47 mm tall.

References: Datasheet & ¹⁰⁴⁰. Type EH90 was first introduced^¶ in 1954.

 
Pin Connections

B7G	1	2	3	4	5	6	7
	g1	k,g5	h	h	a	g2,g4	g3

 
Absolute Maximum Operating Conditions^¶

Heptode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm
	6.3	0.3	100	30	-1	0.75	1.1	1M	0.95

Thanks to Frank Philipse for supplying the above PDF datasheet

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