UT501C Insulation Resistance Tester, with their new design, large scale integrated circuit and digital circuit, is utilized to measure insulation resistance, alternating voltage and other parameters. The tester has features of complete functions, high accuracy, stable performances, comfortable and reliable operation. The tester is used in maintenance, test and verification for various electrical equipment and is applicable to measure insulation resistance of transformer, motor, cable, switch, electric appliances, etc.