This circuit was found in an 80's Electronic Engineering. The power supply must be symmetrical. The no value components are calculated for the desired frequency.
This circuit using components that are still common in our market was found in a 1987...
The varactor or varicap diode tunes the signal for listening to SSB signals on a common receiver. The...
This circuit that also serves to control LEDs and other loads is from a 1960 publication. The...