High-Precision, Wide-Ratio, Self-Balancing Current Comparator

The current proportional standard device is the most important equipment in the traceability system of current proportional values. Due to the influence of magnetic and capacitive errors, existing current proportional standard devices have the characteristics of high precision and wide variation ratio. This article focuses on the current comparator based on the zero magnetic flux principle, and combines electronic compensation technology with magnetic and capacitive error analysis to develop a new type of wide-variable-ratio self-balancing current comparator. It can achieve many ratio transformations while maintaining high accuracy levels. It can be used to calibrate high-precision standard currents of 0.001 level and below, greatly improving work efficiency. The principle and structure of the wide-variable-ratio self-balancing current comparator are described in the article, and its error performance is theoretically analyzed. Error calibration experiments are also conducted. The test results show that the accuracy of the current comparator with a wide range ratio meets the requirement of 0.0002 level, which can be used to solve the problem of high accuracy and low efficiency in wide range current ratio calibration tests.