This circuit is from the LM107 manual. This operational is from the 80s, but the configuration is valid for any operational. The formulas give the gain of the circuit.
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...