Static meter calibrated with direct current - has voltage test circuit and current test circuit with inverting amplifier

摘要

The second of the two test voltages is connected to the control input of a current source and, by way of an inverting amplifier, to the control input of another current source. The outputs of the two current sources are connected to a switch controlled by the voltage-pulse transformer. The output current from the two current sources consists of a constant portion and a fraction proportional to the control voltage of the current source. The current path of the switch on the output side can be connected by a resistor to a voltage source which supplies the two current sources at the same time.