Dear Aspirant,

First to give you a simple answer to where DC current is used, you could look up to your mobile phone's battery. It is working on DC current. DC current is short form for Direct Current, it is the current advocated by Thomas Edison, before Tesla give us Alternating current(AC) used in your house.

In DC current the current flows directly in one direction uniformly unlike AC current in which current changes its direction. The graph for DC is a straight line.

Hope this helps. Thank You.