This circuit is from the 80's integrated circuit manual itself. The component is not as common today as the MOS transistor used. The circuit can be adapted for modern applications.
The figure shows how to use an LM3914 with a variable range moving point. The circuit has an...
This circuit was found in a 90s Popular Electronics. It uses a varicap that admits equivalents. The...
This circuit is from an Electronics Now from 1998 and can be easily assembled with other JFET...