Abstract: The invention refers to a method of measuring resistance of the resistive sensor (5), where the value of resistance of the resistive sensor (5) is determined from its series connection with actively controlled resistor network (3) with selectable value of resistance and with a periodic waveform voltage source (7), and further a device for measuring resistance of the resistive sensor (5) including a periodic waveform voltage source (7), actively controlled resistor network (3), and a resistive sensor (5), wherein the terminals of the periodic waveform voltage source (7) are connected to node A (2) and C (6), terminals of actively controlled resistor network (3) are connected to node A (2) and B (4), and terminals of the resistive sensor are connected to node B (4) and C (6), thus forming a connection in a resistive voltage divider with an automatic selection of one resistor of the divider, and usage of this method for measuring time-varying resistance of the sensor.

Abstract: The method for measuring of quick changes of low surface conductivity of dielectrics under electromagnetic interference of line voltage is based on a comparison measurement on a voltage divider and synchronisation of measuring pulses with periodic sinusoidal course of interference when voltage with pre-set parameters of square pulse is brought to the tested dielectric surface and potential is sampled in the voltage divider consisting of the measured dielectric surface and a resistor with preselected resistivity in certain time intervals both before application of the measuring pulse and immediately before its end, and then based on a difference between the values measured using a differential amplifier, the value corresponding to that measured without effect of electromagnetic interference 60 Hz is derived and the result is the possibility to measure quick changes of low surface conductivity of dielectric surface.