215A

Hendrik Johannes van der Bijl (WECO, USA) developed this first WECO tube. It is also called peanut-tube for it's very small size. As Type N it has been finished in 1919 and was on market as 215A in the early 20ies - for nearly a decade.

The earliest type of 215A tube had a bakelite 4 contact base which was 16 mm diameter and had a metal locking pin on the side, with the bulb diameter being 13 mm diameter. in 1922 the bulb size was increased to 16 mm diameter. Various methods of supporting the element structure were adopted over the tubes' economic life. In later tubes, the locking pin was also bakelite and some tubes had magnesium flashing.

H.J. van der Bijl deducted the fundamental functional relationships of triodes and by that won a post at the Western Electric Company (WECO) as Senior Research Phyicist until the publication of the book "Theory of the Thermionic Tube and its Applications" in 1920. (EE)

The peanut-tube was also produced in Canada by Northern Electric.
In UK ST&C (Standard Telephone & Cables, London) has produced the 215A as 4215A (with adapter to B4 socket) and as 4215AB (with B4 base) to fit European standard socket. Tyne, p.370.

215A: nach Western Electric 1933 Robert Schmalstieg	Just Qvigstad	215A: KoBi Konrad Birkner † 12.08.2014 More ...

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