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.
An interesting type of sensor for specific applications is the sensor formed by piezoelectric...
-- This old oscillator takes advantage of a transistor radio output transformer of the time. The 2...
This circuit shuts off and locks the power to a load in the event of a failure. The circuit is from...