Sargrove sprayed-circuit radio receiver (experimental model) c 1940s.
© Science Museum / Science & Society Picture Library
John Sargrove (1906-1974) was a British engineer who in the 1940s built machines that could make not just printed circuit boards but also complete radios like the one shown here. His machines sprayed plastic blanks with metal to form circuits including resistors, inductors and capacitors. They even attached large components like valve holders. Only valve insertion and final adjustment needed human hands. Sargrove's ideas were sound but his machines were thought to threaten jobs.