This 1965 circuit uses a Philips 4068 tube to measure extremely small charges. The circuit has as indicator a micro ammeter and the transistors are of the time.
This circuit was obtained from a Radio & Electronics Constructor from March 1976. The magazine no...
This bistable touch sensor circuit uses a relay and is very sensitive. We found it in a 1990...
This FM receiver tuning step circuit was found in a 1960 documentation. No information about the...