Sensibly equivalent¶ to:
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 Marconi paper logo.
The thin glass tube envelope measures 18 mm in diameter and the excluding the B7G base pins, is 45 mm tall.
References: Data-sheet, 3002 & 1043. Type 1S5 was first introduced in 1940. See also 1940 adverts.
Absolute Maximum Operating Conditions¶
Updated March 12, 2022.