Four-terminal-method high-value capacitor impedance measuring device and measuring method thereof

Abstract

The invention relates to a four-terminal-method high-value capacitor impedance measuring device and a measuring method thereof. The measuring device includes an inductive shunt, a capacitance box, a standard resistor, a resistance box, a capacitor to be measured, a digital voltmeter and a power supply; the inductive shunt includes a pair of windings with a turns ratio of 1 to 1; the capacitance box and the standard resistor are connected in series to form a measuring loop A; the resistance box and the capacitor to be measured are connected in series to form a measuring loop B; the pair of windings of the inductive shunt are reversely connected to the two measuring loops; and the standard resistor and the capacitor to be measured are connected by adopting a four terminal method. By adjusting impedance balance, the measuring method enables current vales in the two measuring loops to be equal, and a series connection equivalent capacitance value and a loss factor of the capacitor to be measured are obtained through a discrete Fourier transformation method and synchronous sampling technology. The four-terminal-method high-value capacitor impedance measuring device and the measuring method thereof in the invention realize isolation measurement and floating-ground measurement, interference of the power supply to the measuring device can be eliminated, and a calibration result can be prevented from being affected by electric current, thereby greatly improving accuracy of capacitance measurement.

Description

technical field [0001] The invention relates to a measuring device in the field of electromagnetic measurement, in particular to a four-terminal method high-value capacitive impedance measuring device and a measuring method thereof. Background technique [0002] In recent years, domestic and foreign manufacturers have produced various physical and equivalent high-value standard capacitors, with an accuracy of 0.05% to 2%, and a capacity of mF level. These standard capacitors are in urgent need of verification or calibration; commonly used impedance measuring instruments, Such as GR7600, Agilent4284A, etc., also need to be verified or calibrated in the range of high value capacity. However, my country has not established a traceability system for high-value capacitors. When measuring high-value capacitors, some manufacturers and metrology departments often use uncalibrated impedance measuring instruments for measurement, which cannot guarantee the reliability and accuracy of ...

AI Technical Summary

Problems solved by technology

[0009] In order to solve the problem of relatively large measurement errors in the prior art, the present invention provides a four-terminal high-value capacitive impedance measuring device and measurement method, which utilizes a new four-terminal high-value capacitive measurement that combines inductive shunt technology and sampling technology. The method realizes the capacity measurement of capacitors with a capacity range of 10μF to 1mF and a frequency range of 100Hz to 1kHz

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