Sinclair C5 major consumer organisations published sceptical evaluations. The Automobile Association questioned many of Sinclair's claims in a report published at the start of May. It found that the range of the vehicle was typically only about 10 miles (16 km) rather than the promised by Sinclair, and reported that the C5's battery ran flat after only on a cold day. The C5's running speed was more usually around than the claimed , while its running costs compared unfavourably to that of a petrol-driven Honda PX50 moped. The stability, general roadworthiness, and especially the safety of the C5 were questioned, and the
Clive Sinclair 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