Power in terms of science usually referred as the energy for work, everything in this high-tech world requires energy to operate .This energy can be either physical , chemical or mechanical. Digital electronic devices takes electrical energy as input .Say, It is your favourite smartphone , watch or  electric car they all require electrical energy for proper functioning. source: hardwarezone.com.sg This energy can be obtained from batteries , solar panel or Home electric supply. Electrical energy supply can be categorized into AC(alternative Current) and DC(direct current).They have different applications in our daily life. Why is this the matter of talk? Today we are surrounded by electronic gadgets . It could be your laptop ,smartphone or something else . All these products are powered by some kind of electrical energy. To provide stability and mobility these products are lashed with high tech advance batteries .