Vintage Germanium Thorn-AEI (Family) Transistors

The early history of British Semiconductor manufacturing is pretty convoluted. There are many different brands which ended up being manufactured by the same company, and some major brands which remained from long gone acquisitions.

Mazda was a brand in Britain from 1911, initially for light bulbs, eventually transferring to the Thorn company. Thorn also acquired the Brimar brand when STC's Valve (Tube) and CRT business was acquired in 1960.

Thorn Electrical Industries then created a JV in 1961 with AEI, itself a combination of British Electrical manufacturers. The plan was to pool its combined activities in Valves, CRTs and Semiconductors. Manufacturing was in Brimsdown (adjacent to Ponders End - the site of the Edison Swan Company).

EDISWAN transistors were also part of the group, and its transistors were manufactured in Ponders End.

The original Cosmos Lampworks factory built in Brimsdown was adjacent to the equivalent Edison Swan factory. Through acquisition and growth it seems the factories physically combined, and it's likely that EDISWAN transistors were built in the same place as Thorn, Brimar, Mazda and AEI transistors.


However, it's not the whole truth as the CV list had AEI and Brimar transistors manufactured in Kent




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