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.
This circuit generates trains of pulses in regular intervals determined by R1 and C1. The...
This circuit was found in a 1977 Radio Shack documentation. The unijunction transistor can be...
In the figure we show how to use a varicap to modulate a signal in frequency. The circuit can be...