A power source is a device that converts other forms of energy into electrical energy and supplies it to an electrical circuit (or electronic device).
Power sources operate based on the principle of "generating electricity from magnetism," deriving their power from renewable sources-such as hydropower, wind power, tidal energy, water pressure differentials in dams, and solar energy-as well as from the combustion of fuels like coal and residual oil.
Common examples of power sources include dry-cell batteries (which provide direct current) and standard household AC power supplies (110–220 V).