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 the Linear Applications Handbook of the National Semiconductor of 1994. The...
We found this circuit in a 2002 documentation. As it uses still common CMOS integrated circuits, it can...
The presented circuit uses an LM3900, transconductance operational amplifier. It was found in the...