This simple injector and signal follower employs a high impedance headset. Transistors can be of general use. The circuit is from old American documentation.
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...