Why do wall sockets supply alternating current (AC) and batteries supply direct current (DC)?
batteries convert chemical energy to electricity and result is always DC. if battery is chargeable, one can supply power (reverse battery current) to recharge it but if considering only consumption (or only charging) it will always be DC. All energy obtained from nature is always DC (this includes lightning, organisms that can produce electricity etc.). AC was chosen as preferred method of power transfer (Nikola Tesla). transferring power at low voltage requires huge currents (and wires) which was not economical. Tesla devised transfer method that used transformers. Once the power is generated (few hundred or thousand volts), it is converted to very high voltage using transformers. As a result, transmission current is much lower and more economical (since using thinner wires). While transmission is the most significant factor, there are other reasons for AC such as switching. It is much easier to interrupt AC circuit because arc extinguishes when current (sin function) goes through zer
