It is an improved version of the previous circuit with a voltage follower that reduces the load impedance. The circuit was found in American documentation from the 1980s.
This amplifier circuit for listening was found in a book by Hugo Gernsback from 1960. The...
Obtained in a 1969 Ferranti documentation, this circuit dissipates only 2.2 mW with 4.5 V. The...
This circuit was obtained in an old Elektor and can be adapted to use white power LEDs. The...