This circuit was obtained from a 1969 Electronic Design. Transistors admit modern equivalents. The frequency of the signals is set to R2.
This circuit was found in a Popular Electronics from the 90's. The circuit can be used to convert...
This circuit works with only 1.5 V and can be powered by a solar panel. The circuit is from 1991....
In fact, the original American publication exaggerated a little about the range that a good...