This circuit generates signals from 10 Hz to 10 kHz. We found it in a Popular Electronics from the 90's. The components admit equivalents.
This circuit with the 741 operational amplifier was found in the March 1995 issue of Electronics Now...
This circuit was found in a General Electric documentation from 1966. It uses discrete components...
We found this circuit in a French technical documentation from 1982. The circuit can be...