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 circuit is from Motorola's Linear Interface ICs of 1993. The circuit can be powered by...
This circuit activates a relay when the supply voltage drops below the value set in the trimpot. The...
Based on National semiconductor power operational amplifiers, uncommon today, this circuit...