This circuit is from an American documentation from the 90s. The transistors are of power and must be equipped with good heat sinks as well as the integrated voltage regulator.
Published in Popular Electronics with the curious name of Obnoxious Noisemaker, this 1968 circuit...
We found this circuit in the July 1992 issue of Radio Electronics magazine. An optical system...
This circuit was found in an English magazine from 1978, but it is still current, just change the...