Research On The Key Technology Of Precision Four-terminal Impedance Measurement

Capacitance bridge as one measurement system to calculate the capacitance of the capacitor is an important part of the computing device. In order to further improve the measurement uncertainty calculations capacitive means, the capacitor capacitance bridge transfer of a higher accuracy. For the calculation of the reference capacitor is established, transfer capacitance precision capacitance bridge need to reach the order of 10-9. Therefore, the paper four-terminal impedance measurement technology programs re-designed and built for high-precision capacitance bridge four-terminal devices, high precision capacitance delivery. Precision four-terminal impedance measurement technique is to further improve China’s AC impedance traceability system, one of the key technologies to improve the traceability of the AC impedance.For four-terminal capacitor bridge device, the measurement accuracy error is mainly by the coil winding, winding assembly and wiring errors. This article positioning precision four-terminal impedance measurement study the key technologies to terminal pair, on the basis of the theory of inductive voltage divider,the use of three-dimensional graphics and Inventor assembly simulation technology,capacitance bridge required three points induction the pressure for production and analysis and demonstration, solving assembly magnetic shielding and electrical shielding problems. Wherein three inductive voltage divider are: induction divider calibration source and inductive voltage divider ratio inductive voltage divider. In addition, in order to improve the measurement accuracy of the four-terminal capacitance bridge, to minimize transmission errors in the lead, according to the inadequacies of the existing paper chokes designed and produced a new type of active chokes. In the new active choke design verification, the main framework of the special bobbin, a combination of core and amplifying compensation circuit test analysis. Paper design analysis to further improve the accuracy of the capacitor capacitance bridge to pass the ready.