Improvements introduced in self-combined millivoleters for use in geophysical prospection with continuous current. (Machine-translation by Google Translate, not legally binding)

摘要

Improvements improved in the self-compensated milivoltimeters for use in geophysical prospection with continuous current, essentially characterized by comprising a bipolar switch with faculty of polarity change, located immediately after the input terminals, so that the undesirable alternating current voltages, which can accompanying the voltage to be measured are filtered by a capacitor coupled between the input lines, following which a compensating circuit comprising two multi-turn helical potentiometers is provided, by means of which it is possible to compensate the tensions existing in the ground in the absence of the voltage to be measured, while coupled to said potentiometers, there are some resistors, two for each, which serve to limit said compensation margin to ± 500 mv (millivolts). (Machine-translation by Google Translate, not legally binding)