This circuit, of a Popular Electronics of 1969 is destined to firing a gas LASER of the time. The circuit makes use of a high voltage transformer for triggering.
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...