This circuit was obtained in an American documentation from the 80's. The transistors can be equivalent to those indicated and the crystal can reach a few tens of megahertz.
This circuit generates signals from 0.01 Hz to 10 kHz, but uses unusual components today. The...
This 1969 Mullar circuit appears elsewhere on this site. The circuit uses germanium diodes and the...
This control circuit for direct current motors uses a 741 and an operational one of unusual power...