We found this battery eliminator in a Radio Electronics magazine from August 1974. The transistor must be equipped with a heatsink and other voltages can be achieved by replacing the zener.
This circuit was found in a 1977 Radio Shack documentation. The unijunction transistor can be...
Other series amplifiers such as the MC3301, MC3401 and LM2900 can be used on this circuit. We...
This circuit offers excellent sound quality for headphones of 150 ohms or more. The circuit was...