This circuit is intended to increase the width of a pulse. The circuit is TTL and can be used as a shield. We found it in an 80's Electronic Engineering.
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...