This circuit was found in a 90’s Electronic Engineering. The signal is sinusoidal with the frequency given by the non-value components that form the resonant network.
This circuit is indicated for the PX or 11-meter band, having been found in a 2003 documentation. The...
This configuration from a 1976 technical documentation shows how to use a varicap in a direct...
Other operational amplifiers can be used in this circuit obtained from the manufacturer's own...