Variational Method of Calibration of Impedance Meters. Part 2. Implementation of Method
Implementations of the variational method in transformer bridges with inductively coupled arms and in logometric bridges based on an operational amplifier with high amplification factor are described. It is shown that through the use of the variational method in transformer bridges it is possible to eliminate the influence of the basic error sources – impedances in connecting cables and transformer windings – and, in logometric bridges, by means of this method, eliminate the effect of the finite amplification factor of the operational amplifier and its input impedance on the measurement results. Theoretical and experimental investigations have shown that the measurement error may be reduced 100- and 1000-fold through the use of the variational method. Metrological data from impedance meters developed with the use of variational methods are presented.
Keywordstransformer bridge with inductively coupled arms impedance capacitance inductance resistance transfer ratio gain variation calibration
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