Using a varactor or varicap, this 1969 Electronics World circuit has a modulation range from 75 kHz to 52 MHz. Modern equivalent components can be used.
This circuit is one of many that the reader can find in this section for testing crystals. The...
I found this circuit on a December 1976 Radio Elettronica. The Italian magazine no longer exists, but...
June 2017 - Mouser Electronics has in stock the new AC Metallized Polypropylene Film Capacitors...