Found in a 1967 RCA manual, this circuit uses components from the era that can be replaced by modern equivalents. The circuit is for resistive loads.
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...