This circuit is from a Radio Electronics magazine from August 1990. The circuit uses components from the time and is suitable for measurements in alternating current.
This TTL dice was found in an old American 1980s documentation, but can still be easily assembled....
This circuit for several frequencies was obtained in an American documentation from the 90s. The...
November 2016 - Vishay's new proximity sensors VCNL4100 for display presence and activation,...