Suggested by Sprague in the 1980s documentation, this circuit can control three-phase AC motors. The original documentation does not specify the maximum motor current.
This basic Schmitt trigger was found in an American publication from 1968. The circuit uses...
This circuit is from an American 1964 documentation. Transistors of the time are used, but modern...
This simple circuit uses small speakers for both listening and speaking (microphone). The feeding is...