The EC903 is a high frequency triode for television front end use. The grid is connected to pins 2 and 6 and these are opposite one another on the base. Similarly the anode is connected to opposing pins 1 and 7.

The construction is substantial for a small signal device. The anode dissipation is 2 watts and this also seems high until one realises that the noise figure is reduced as the anode current is increased. Thus this is a low noise. by valve standards, UHF device and was probably run in a cascode configuration.

The thin glass tube envelope is 17.7 mm in diameter, and excluding the B7G base pins is 36 mm tall.

 
Pin Connections

B7G	1	2	3	4	5	6	7
	a	g1	h	h	k	g1	a

 
Absolute Maximum Operating Conditions

Triode	Vh	Ah	gm	μ
	6.3	0.2	6.0	15

This exhibit was last updated on 24 November 2007