List any 3 differences between AC & DC current
The electric current which changes its direction (or polarity) after certain fixed interval of time is called ac or alternating current. Thus , in ac, the polarity ( + or - ) is not fixed and its current V/S time graph is like a wave.
The electric current which flows in the same direction is called direct current or dc. Thus in dc the polarisation ( + or - ) are fixed The current obtained from a cell or battery is dc. The current V/S time graph is a straight line parallel to time axis.