Basic need of any project i.e power source

when you start to make any project related to any field weather it is electronics ,electrical or mechanical,first of all we look for power source.Power source is the basic need to run any  project.to any project power can be given electrically or mechanically.When we select electric power source there are again 2 ways to give power first one is AC(Alternating Current) other one is DC(Direct Current) .As we know that in electronics we use very less power i.e 2.5 v to 12 v,so it is easy to use battries.But battries have some life ,after some time battries do not give any power,so then we have to charge it again.Moreover if we want to use AC to apply power we have to convert it to DC.in the next post we  will show you how to convert 220 v AC to 5 or 12 v  DC,and how to chargr yor car, bike battries.