AC generator generators alternating current that flows in one direction in one half of the cycle and the other way, in the other half cycle. There are rotors, stators, rotating coil, load and permanent magnets in the AC generator.
DC generator Also has same structure as the AC generator. In addition, it uses a commutator ring. The direction of the current flow is reversed exactly at half cycles of the potential generated due to induction. So the final current that flows into the load is always in one direction. Then additional electrical circuits (including capacitors) are used to bring the varying sine wave shape to a reasonably constant voltage level.