This 8 W amplifier with germanium transistors was found in a Japanese documentation from 1967. The circuit is of the commercial type and is powered by two 12 V batteries or by a symmetrical source.
In the figure we have the way to use a common operational amplifier for AC signals. The resistor...
This configuration presents a negative resistance caracteristic such as the one found in...
The transistors of this circuit found in a 1965 magazine can be the BC558 and the sensitive 12 V x...