Study on the problem of channel-closing of multi-channel comparator for heavy direct current

To solve the problem of channel-closing of multichannel comparator for heavy direct current, a new method is proposed that an air gap is set between every two channels in the DC comparator. This method fairly prevents the channels of multi-channel comparator from closing, and guarantees high precision measurement. By calculation, the comparator of four channels, with the total length of air gaps to be 3.2 mm and the length of each gap to be 0.8 mm, has the current ratio accuracy higher than 5 times 10^-4 when applied for industrial measurement.