This circuit was found in an English publication from 1967. The circuit is for listening on a phone. Transistors are types of germanium of the time.
In the figure we have the way to obtain an adjustable constant current source of 2 mA. The...
We found this circuit in a Popular Electronics of the 90s. The circuit can be easily mounted...
This circuit provides an output voltage approximately 2 times that of the input voltage. The...