Accurate resistance comparators with ratiometric digital multimeters

This summary paper describes and characterizes two resistance comparators exploiting long-scale digital multimeters operating in ratiometric mode and compares the results obtained in the measurement of resistance ratios of 12.906kΩ : 10kΩ and 10kΩ : 1kΩ against those obtained with a direct current comparator. The comparators herewith described are suitable for primary resistance metrology with accuracy at the 10 −8 –10 −7 level, depending on the resistance ratio.