A self-calibration method for high-precision direct current comparator

To solve the problem of calibrating high-precision heavy direct current comparator and related metering device, a self-calibration method based on small current differential principle is proposed, and the formulas based on the method are derived. This method fairly prevents the difficulty from measuring weak signal, and can accurately and easily calibrate 1×10^-5~1×10^-7 current ratio-error for high-precision direct current instruments by choosing appropriate measurement parameters based on the formula in this paper. And the validity of the method is proved by experimental data.