English entrepreneur and inventor Sir Clive Marles Sinclair was born 30 July 1940. He is most commonly known for. his work in consumer electronics in the late 1970s and early 1980s. Sinclair’s micro Kit was formalised in an exercise book dated 19 June 1958 three weeks before his A-levels. Sinclair drew a radio circuit, Model Mark I, with a components list: cost per set 9/11 (49½p), plus coloured wire and solder, nuts and bolts, plus celluloid chassis (drilled) for nine shillings (45p). Also in the book are advertisement rates for Radio Constructor (9d (3¾p)/word, minimum 6/- (30p) & Practical Wireless (5/6 (27½p) per line or part line). Sinclair estimated producing 1,000 a month, placing orders with suppliers for 10,000 of each component to be delivered. Sinclair wrote a book for Bernard’s Publishing, Practical transistor receivers Book 1, which appeared in January 1959. His practical stereo handbook was published in June 1959 in total he produced 13 constructors’ books and the last book Sinclair wrote as an employee of Bernard’s was Modern Transistor Circuits for Beginners, in 1962.
After spending several years as assistant editor of Practical Wireless and Instrument Practice, Sinclair founded Sinclair Radionics in 1961, His original choice, Sinclair Electronics, was taken; Sinclair Radio was available but did not sound right. Sinclair Radionics was formed on 25 July 1961.Sinclair made two attempts to raise startup capital to advertise his inventions and buy components. He designed PCB kits and licensed some technology. Then he took his design for a miniature transistor pocket radio and sought a backer for its production in kit form. Eventually he found someone who agreed to buy 55% of his company for £3,000 but the deal did not go through. Sinclair, unable to find capital, joined United Trade Press (UTP) as technical editor of Instrument Practice. Sinclair appeared in the publication as an assistant editor in March 1962. Sinclair described making silicon planar transistors, their properties and applications and hoped they might be available by the end of 1962. Sinclair’s obsession with miniaturisation became more obvious as his career progressed. Sinclair undertook a survey for Instrument Practice of semiconductor devices, which appeared in four sections between September 1962 and January 1963. His last appearance as assistant editor was in April 1969. Through UTP, Sinclair had access to thousands of devices from 36 manufacturers. He contacted Semiconductors Ltd (who at that time sold semiconductors made by Plessey) and ordered rejects to repair. He produced a design for a miniature radio powered by a couple of hearing aid cells and made a deal with Semiconductors to buy its micro-alloy transistors at 6d (2½p) each in boxes of 10,000. He then carried out his own quality control tests, and marketed his renamed MAT 100 and 120 at 7s 9d (38¾p) and 101 and 121 at 8s 6d (42½p). He also produced the first slim-line electronic pocket calculator in 1972 (the Sinclair Executive).
In 1973 Sinclair moved into the production of home computers and formed another company, initially called Ablesdeal Ltd. This changed name several times, eventually becoming Science of Cambridge Ltd, and In 1978 they Launched a microcomputer kit, the MK14, based on the National SC/MP chip. By July 1978, a personal computer project was under way. When Sinclair learned the NewBrain could not be sold at below £100 as he envisaged, he turned to a simpler computer. In May 1979 Jim Westwood started the ZX80 project at Science of Cambridge; it was launched in February 1980 the UK’s first mass-market home computer for less than GB£100, at £79.95 in kit form and £99.95 ready-built. In November, Science of Cambridge was renamed Sinclair Computers Ltd.In March 1981, Sinclair Computers was renamed again as Sinclair Research Ltd and the Sinclair ZX81 was launched at £49.95 in kit form and £69.95 ready-built, by mail order, and it is widely recognised for its importance in the early days of the British home computer industry.In February 1982 Timex obtained a license to manufacture and market Sinclair’s computers in the United States under the name Timex Sinclair. In April the ZX Spectrum was launched at £125 for the 16 kB RAM version and £175 for the 48 kB version. In March 1982 the company made an £8.55 million profit on turnover of £27.17 million, including £383,000 government grants for the TV80 flat-screen portable television.In 1982 Sinclair converted the Barker & Wadsworth mineral water bottling factory into the company’s headquarters. (This was sold to Cambridgeshire County Council in December 1985 owing to Sinclair’s financial troubles.)
The following year, he received his knighthood and formed Sinclair Vehicles Ltd. to develop electric vehicles. This resulted in the 1985 Sinclair C5. In 1984, Sinclair launched the Sinclair QL computer, intended for professional users. Development of the ZX Spectrum continued with the enhanced ZX Spectrum 128 in 1985 . In April 1986, Sinclair Research sold the Sinclair trademark and computer business to Amstrad for £5 million. Sinclair Research Ltd. was reduced to an R&D business and holding company, with shareholdings in several spin-off companies, formed to exploit technologies developed by the company. These included Anamartic Ltd. (wafer-scale integration), Shaye Communications Ltd. (CT2 mobile telephony) and Cambridge Computer Ltd. (Z88 portable computer and satellite TV receivers). By 1990, Sinclair Research consisted of Sinclair and two other employees, and its activities have since concentrated on personal transport, the Zike electric bicycle, Zeta bicycle motor and the A-bike folding bicycle for commuters, which weighs 5.5 kilograms (12 lb) and folds down small enough to be carried on public transport.