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 has been found in an old documentation, but can be used as input shield for current...
This circuit generates signals from 0.01 Hz to 10 kHz, but uses unusual components today. The...
This circuit was found in the June 1969 issue of Radio Electronics magazine. The circuit uses a...