The 5A/170K is a special quality high slope RF beam tetrode primarily intended for use in wideband amplifiers in telephone carrier systems, radar equipment and measuring equipment. STC stands for Standard Telephones and Cables.

It can be seen that in this miniature envelope is an even smaller valve, this very small size helps to reduce inter electrode capacitances and thereby raises the maximum usable frequency that the device can operate at.

These valves would be used up to the UHF region of the spectrum. In telephone systems a single carries has a large number of separate telephone calls modulated upon it

The thin glass tube envelope is 21 mm in diameter and, excluding the B9A base pins, is 33 mm tall.

 
Pin Connections

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

 
Absolute Maximum Operating Conditions

Beam Tetrode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm
	6.3	0.3	190	160	-1	13	3.3	35K	16.5

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 04 July 2009