At present conventional QJ44 type double-arm DC bridges are commonly used in power systems to measure contact resistance and the test current of such bridges is only mA level and it is difficult to find defects in reducing the cross-sectional area of the loop conductor. When measuring the contact resistance of the high-voltage switch conductive loop the measured value is several times larger due to the influence of the oil film and the oxide layer between the contacts and the contact resistance value cannot be truly reflected. To this end the latest Ministry of Power Standard DL/T845.4-2004 "General technical requirements for resistance measuring devices: loop resistance tester" and the new version of the verification procedures JJG1052-2009 "loop resistance tester straight resistance test procedures" made a measurement ( Isolation) The measuring current of the contact resistance of switches circuit breakers etc. is not less than DC 100A and the minimum current maintenance time is not less than 60S ensuring accurate test results. The High Precision Micro Ohmmeter operator panel is ergonomically designed to meet operational habits and uses high frequency switching power supplies and digital circuit technology for the measurement of loop resistance in switch control equipment. The test current is DC 100A and 200A recommended by national standards. The loop resistance can be directly measured under the condition of DC 100A and 200A. The test result is displayed by large-screen LCD LCD and has functions of data storage output printing time setting etc. and 50A 150A gears for users to choose; custom Test time the maximum setting time is 599S which is larger than the standard 60S; it is a very stable contact resistance tester with a resolution of 0.01�¼�© in China and its performance exceeds the imported high current micro-ohmmeter. It meets the requirements of on-site high-voltage switch maintenance of electric power and power supply departments and loop resistance test of high-voltage switch factory. Product nickname Contact resistance tester switch loop resistance tester contact loop resistance tester contact (loop) resistance tester High Precision Micro Ohmmeter