Comparison between MC and MI Instruments S.No M.C Instruments M.I Instruments 1 More accurate Less accurate 2 Costly cheap 3 Uniform scale Non-uniform scale (scale cramped at beginning and finishing) 4 Very sensitive Robust in construction 5 Low power consumption Slightly high power consumption 6 Eddy current damping is used Air friction damping is used 7 Can be used only for D.C Can be used on A.C as well as on D.C 8 Controlling torque is provided by spring Controlling torque is provided by gravity or spring 9 θ α I θ α I 2 10 Errors are set due to aging of control springs, permanent magnet (i.e. No Hysteresis loss) Errors are set due to hysteresis and stray fields (i.e. hysteresis loss takes place).