This amplifier step for small signals can use any general-purpose transistor like the BC548. The circuit can be powered by voltages from 6 to 12 V.
This circuit was found in a documentation of the year 1958. The transistors are germanium types...
Found in a 90’s 303 Circuits, this circuit uses components that are still common and has a common...
We found this circuit in a 1990 documentation. It is totally up to date by the components it uses...