Found in American documentation this circuit uses transistors of the time. The circuit can be made with current components. It works as a trigger working with 600 ohm signals.
This circuit was obtained from an American 1980s documentation. The frequency depends on the...
New Low-Power PIC24 “GA7” Microcontroller Family Now Available CHANDLER, Ariz., Dec. 12, 2016 — The...
We find this circuit in an English 80's documentation. The circuit can be made with more modern...