It was formed in 1961 as "Sinclair Radionics" and sold electronics components, audio amplifiers, radios, small TVs, pocket calculators, and digital watches. In the early 1980s, the company split into two parts as "Thandar Electronics" and "Science of Cambridge," the latter renamed "Sinclair Computers" and then "Sinclair Research," which rose to success with the releases of the ZX80, the ZX81, and the ZX Spectrum home computers. The company's U.S. offices were in Nashua, New Hampshire.
The company followed those successful products with the Sinclair QL (short for Quantum Leap) which, despite its technical merits, sold poorly. The C5 electric car, a supposedly cheap and efficient form of transport from the spin-off company "Sinclair Vehicles," was perhaps a bigger commercial disaster. The rights to all Sinclair Research computer products were bought by Amstrad in 1986. Sinclair Research continues to exist, and its founder continues to work in research, recently inventing an ear-piece radio and an electric bicycle motor.
Recently, Sir Clive Sinclair announced that his company is working to a new version of electric car called C6, that should be released in 2004.
Sinclair products were in some ways typical of British engineering of the period, sometimes huge successes, and sometimes embarrassing commercial failures. The calculator watch, for example, required so much power from its meager battery that the battery would often have expired by the time the watch was purchased.
Sinclair's early products are now often highly sought after. A ZX80, for example, can fetch up to £200 in an online auction on eBay. The range of calculators are also extremely popular with collectors, as is the 'DIY' digital watch.