Advantages and Disadvantages of Moving Iron Instruments Advantages 1. The instrument can be used both on DC as well as on AC circuits. 2. These instruments are cheap, robust and simple in construction. 3. The instruments have high operating torque. 4. The instruments are reasonably accurate. 5. These instruments can withstand overload momentarily. Disadvantages 1. Scales of these instruments are not uniform because of pneumatic damping. 2. Errors are introduced due to change of frequency I case of A.C. 3. Errors are introduce due to hysteresis and stray magnetic field. 4. Power consumption is high.