This circuit was found in a 1945 publication. The circuit was stated to be part of a walk talkie. Note that, as it is a portable assembly, it was powered by batteries. The jack was for microphone insertion.
In the figure we show a widely used configuration for the CA3140. The power of this circuit can be...
The circuit shown was found in a Japanese publication from the 1960s. Transistors can be...
This circuit was obtained in a Popular Electronics of the 90s. The circuit can be assembled with...