This circuit, very critical due to the frequency at which it operates, was found in an American documentation that uses a resonant cavity in a beer can. The transistor can be of any type for RF.
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...