We found this circuit in the March 1995 issue of Electronics Now magazine. The circuit has a frequency range determined by C1 and R3. The signal generated is square.
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...