We found this circuit that converts a direct voltage into a proportional frequency signal. The circuit is from an Electronics Now from April 1993. The JFET can be of any type.
This very low ripple and high voltage circuit was found in a technical documentation from the 70s,...
We found this circuit in an American 1980s documentation, but it can be implemented with modern...
Here is a very simple robot circuit that follows the line driven by a small 3 V sevomotor that...