QJ36a DC digital double arm bridge is a kind of 5 and a half digit desktop digital DC resistance tester composed of high stability precision constant current source, high precision digital voltmeter with self calibration and CPU microprocessor. Its measurement results are displayed by 6 digit VFD fluorescence. The instrument has the characteristics of low price, high measurement accuracy, stable performance and convenient use. It is suitable for measuring the resistance value of various wires and cables, various coils, motors, transformer windings, especially with self calibration function (users can use BZ3 standard resistance for calibration), improve the accuracy of the instrument, and save the inspection time of the operators. Therefore, the instrument is widely used in factories, scientific research units, working places and laboratories.