This small audio amplifier was found in an American publication in 1975, The integrated circuit used is rare today. The circuit was used in portable receivers of the time and other 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...