Generator can convert mechanical energy into electrical energy, battery can convert chemical energy into electrical energy.
Generator, battery itself is not charged, its poles respectively positive and negative charge, positive and negative charges generated by the voltage (current voltage is charged under the effect of the formation of directional movement), where the conductors do have a charge, to produce a current only need to add a voltage when the battery terminals connected to a conductor in order to generate electricity and put out the release of positive and negative charges, when the charge cleared, will make the flow of charge (pressure) disappeared. Batteries and so called power. Through the transformer and rectifier, the AC into DC power rectifier device called. To provide an electronic device called a signal source. Transistor can be sent the signal amplification, the amplified signal is transmitted again to the back of the circuit to go. Transistor on the back of the circuit can also be seen as a signal source. Rectifier power, sometimes called the power source.