Using the 741 this basic circuit was found in the November 1973 Radio Electronics magazine. The power supply must be symmetrical. The components can be recalculated for other frequencies.
We found this circuit in an English documentation from 1979. It shows how you use a 100 uA...
This circuit was found in an EDN from the 90s. For the components indicated, the frequency is 10 kHz....
This is a very interesting automation that can be adapted for other types of applications. In...