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.
This circuit was found in an American 1980s documentation. The components are current but most...
This circuit was found in an old GE SCR manual. The SCR must be in accordance with the relay and...
This circuit measures millivolt voltages. The corresponding current range of the multimeter can be...