This high-speed circuit was found in 1980s Linear Technology documentation. The circuit makes use of components of the time with TTL output and TTL input that enable their use as a shield.
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...