For an 8 ohm load, this Motorola circuit was found in a 1968 documentation. The transistors are of the time and the power supply must be symmetrical.
Found in American documentation from the 1970s, this circuit employs an integrated circuit from...
This circuit was obtained in the publication 101 Electronics Projects of 1979. The circuit can be...
This assembly circuit using a small motor as a generator was found in Radio Electroics magazine from...