Found in Motorola documentation from the 90's, this circuit has a high input impedance. The power supply must be symmetrical. The circuit can be implemented with modern operational amplifiers.
We found this circuit in an American documentation from the 60s. The circuit can be made with...
This simple circuit uses few common components and can be installed in any car. In case of...
This amplifier step with a transistor has an input impedance of 100k to 10 M. The transistor can be any...