The integrated circuits used in this oscillator are not very common today, as we obtained it in documentation from the 1980s. The circuit must be powered by a symmetrical source.
The circuit shown is from an old European publication. In it we have the way to activate a relay...
We found this circuit in a European publication from the 1990s. Transistors are still common types...
This circuit was found in an American documentation and can be added to common amplifiers of any...