This circuit was obtained from an American documentation from the 1970s. Information on the current obtained and the winding of the transformer is not given.
This circuit that imitates the sound of the cowboys' calls with their “louder” was found in a...
This circuit with JFET was obtained in a book on FETs of 1989. The circuit is still current since...
The circuit is from Ferranti's 1974 transistor manual. Transistors are general purpose types, and...