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.
In the figure we have the basic way of using the 3-and-a-half-digit counter 7107. The circuit is...
We found this simple outlet tester using neon lamps in a Radio Electronics magazine from August...
The figure shows a simple way to obtain a negative voltage from a common source configuration. The circuit is...