|Due to moving parts there are losses and friction at bearings.
||As there are no moving parts,mechanical losses are reduced.
|Accuracy is less compared to digital wattmeters.
||Accuracy is high as compared to analog wattmeters.
|Error may take place at the time of reading the scale due to its non-linearity.
||Digital display facilitates to read the power in fraction and in correct fashion.
|It does not required any auxiliary supply.
||It required auxiliary d.c. supply work.
|More reliable as no complications in design and avoidance of electric components.
||Reliability is less as compared to analog to work.
|No effect of supply transients on performance of meter.
||Any supply transients may damage the wattmeters.
|More stable to vibration and temperature variations.
||Considerable effect of vibration and temperature on performance of electric components.