factories in
Southampton and
Hazel Grove, Stockport, Cheshire. Southampton (Millbrook Trading Estate) was a purpose-built plant, opened in 1957 for the manufacture of
semiconductors. Production of germanium alloy
transistors was transferred from Mitcham. At the same time the plant started the research, development and production of electro optical devices. Fabrication of planar devices on a mass production basis did not begin until 1966, when germanium sales were decreasing. 1967 saw the start of the development and production of
integrated circuits. The plant was planned to be the biggest semiconductor facility in Europe, employing 3,000 people including 200 scientists and engineers. In 1962 Associated Semiconductor Manufacturers (ASM) Ltd was formed by Mullard and
GEC to combine the semiconductor development and production facilities of the two companies; Mullard owned two-thirds of the company and included the Southampton plant; GEC contributed their small factory in School Street, Hazel Grove, producing
thyristors,
rectifiers and power
diodes. GEC pulled out of ASM Ltd in 1969. In 1972 production was moved to a newly constructed factory nearby on Bramhall Moor Lane. Both sites were later owned by
NXP Semiconductors (formerly
Philips Semiconductors). The Southampton site is now closed. Hazel Grove, Stockport specialises in
power semiconductor devices and is now
Nexperia Manchester. The first
transistors produced by Mullard were the OC50 and OC51 point-contact types in 1952, which were not widely used. In 1953 Mullard moved to junction transistors, beginning with the plastic-cased OC10 series. These were followed by the glass-encapsulated OC43...47, OC70/71, (released in 1957) and OC80 series (the output devices were metal encapsulated to facilitate heatsinking), which were produced in large numbers and copied by other companies, such as
Valvo (another Philips subsidiary) and
Siemens in Germany, and
Amperex (another Philips subsidiary) in the USA. RF transistors were the OC170 and OC171. All these were germanium PNP transistors. Mullard's first silicon transistors were the OC201 to OC207, PNP alloy types using the standard SO-2 metal-over-glass construction such as the OC200 shown. From about 1960 Mullard switched to using the BC prefix for silicon, and AC for germanium, eliminating the confusion of part numbers. in the mid-1960s the first plastic packages were introduced. In 1964 the company produced a prototype electronic desktop
calculator as a technology demonstrator for its transistors and
cold cathode indicator tubes. ==Space science and astronomy==