This circuit was found in an ancient American documentation. With it is possible to double the frequency of a transmitter For the range of 6 meters obtaining 8 W. The circuit makes use of varicap.
Found in a 90s Radio Electronics, this circuit can be used in high voltage experiments, ionizers,...
This VFO circuit generates signals from 2 Hz to 50 Hz. We found it in Popular Electronics from...
This circuit, published in the 1980s, can be applied to operational amplifiers of almost any type....