Dc resistance tester and multimeter and other instruments are the same as resistance measurement instruments. Both dc resistance and insulation resistance are based on Ohm's law. The only difference between them is the size of resistance measured. Although the theoretical basis of these resistance measuring instruments is the same, but why can't we use a multimeter to measure the DC resistance of electrical equipment such as transformers, so that dc resistance tester improves the measurement speed of test transformers, and has gradually replaced the original single-arm bridge. Of course, because the DC resistance tester is used in precision electronic components, resulting in the measurement of perceptual samples, need to be fully discharged before removing the wire, otherwise it may cause the feedback of large current impact and burn out the instrument. It may not be as bad as single-arm bridge and other traditional instruments, but there is no denying that the progress of science and technology is changing our way of production and life.

Dc resistance measuring instrument is a practical instrument for measuring dc resistance and low voltage switch contact resistance, cable wire or weld interface resistance of various rational loads such as power transformers, heavy motors and mutual inductors. Dc resistance rapid tester is a high-precision replacement of dc single and double - arm bridge. Dc resistance test of transformer winding is an essential test item after transformer handover, overhaul and change of tap switch. By measuring the DC resistance of the transformer winding, we can check the welding or connection quality of the lead wire, whether the winding is short or open between turns, and whether the contact of the tap switch is good. QJ44 double-arm bridge was used to measure the direct resistance in the past, and the measuring current of this kind of bridge is milliampere level, which takes a long time to measure, and the accuracy is low. In order to change this situation, shorten the measuring time and reduce the workload of the tester, the dc resistance rapid tester was developed.