Measuring insulation resistance of telecommunication cable - determining differences between measurements from voltage applied with alternating polarity

摘要

A method of measuring resistances, esp. isolation resistances, involves alternately switching measurement voltage sources to the measurement object and determining the difference between two successive voltage measurements on a resistor. The measurement voltage is alternately applied with reversed polarity for periods dependent on the reactance. The differences between the stored, opposite polarity measurements are amplified and corrected and fed to the voltage meter with noise voltage compensation. USE/ADVANTAGE - For accurately measuring resistances in communications cables in presence of associated reactances and noise voltages.