Now,more than 95 percent of the word's electric energy is produced by generators.
The dry cell is the most familiar and convenient type of all kinds of voltaic electric cells.They are cheap and portable but not permanent. Another type of battery called a storage battery. Though heavy and bulky, it has the advantage of a much longer life. A storage battery can be recharged after it has run down.
All electric cells furnish direct current (DC) that continues to flow through the external circuit in the same direction. Hence the electrons flow in the same direction.
A generator converts mechanical rotational power into electric energy .The two basic forms are the DC generator and the AC(alternating current) generator or alternator.