The Ferranti S2 is a screen grid RF tetrode. It was designated for use as a frequency changer in battery radio receivers where it would be heated by a two Volt accumulator.
The classic envelope is 42 mm in diameter and, excluding the B4 base pins, is 106 mm tall.
References: 1040 & 1043. Type S2 was first introduced in 1932.
Absolute Maximum Operating Conditions¶
Updated January 18, 2013. shape:classic construction:pinch type:tetrode age:1930.1940 base:b4 heater:2.0v pins:4 pin:1.g2 pin:2.g1 pin:3.f pin:4.f pin:tc.a