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.
We have in the figure an ultra-simple alarm found in a 1981 publication. As the author indicates, it is...
Found in an Electronic Design of 1964 this circuit has a control for the frequency and another for the...
The BFO or Beat Frequency Oscillator is used to receive telegraphic signals or even modulated in...