The 1S5 is a diode pentode valve was designed for battery portable radio receivers. This short grid base pentode was designed with particular reference to AF voltage amplification. The 1.4 Volt filament is to be run from a dry cell and the 90 Volt anode rating matches standard HT batteries.

The bright Nickel anode is oval in shape and hides the grids. The filament is a single strand that runs from the base connections, through the electrodes and out of the top mica to a spring support at the top of the valve.

The thin glass tube envelope measures 17 mm in diameter and the excluding the B7G base pins, is 43 mm tall.

 
Pin Connections

B7G	1	2	3	4	5	6	7
	f-	nc	a(d)	g2	a	g1	f+

 
Absolute Maximum Operating Conditions

Pentode	Vh	Ah	Va	Vs	Vg	mAa	mAs	ra	gm
	1.4	0.05	90	90	0	2.7	0.63	0.5M	0.72

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 12 June 2007 {find valves by name}