The Fluke Model 845AR High Impedance Voltmeter-Null Detector is an all solid-state null detector designed for extremely high input impedance, sensitivity, and isolation. As a rack mounted unit, it operates from strictly from an AC line. The 845AR offers 19 ranges from 1 ?V to 1000 VDC. Accuracy of ?2%. Input isolation is greater than 10E+12 ohms. Input may be floated to 1100 V above ground and overload protected to 1100 V on all ranges. Recorder output isolated from input.