A.C.generator and D.C generator

希望你想要既係英文啦。

AC generator and DC generator are different in two ways.

firstly is their structure, secondly is their current given out.

a simple DC generator consists of a coil taht rotates in a magnetic field.
(this is also occurs in an AC generator.)
the difference between an AC and a DC generator is in the way that the current is provided to the external circuit. An AC generator uses a slip rings. A DC generator uses a split ring commutator to connect the rotating coil to the terminals.
(note that a commutator is a switching device for reversing the direction of an electric current.)

In the DC generator the coil is forced to rotate in the magnetic field. this induces the an emf in the coil. the emf is transferred to the externa circuit via the brushes that make contact with the commutator. when the emf of the coil changes direction, the brushes swap over the side of the coil they are connected to, thus causing the emf supplies to the external circuit to be in one direction only.

the out put from a AC generator produce an alternating current by connects the coil to the external circuit or ditributino system by the use of slip rings. slip rings rotate with the coil. the slip rings is connected to the terminals therefore the current direction will change every half turn.

2007-02-26 17:11:01 補充：
即係咁…個dc發電機既設計係 佢每轉半個圈既時候就會有個裝置(commutator)將駁住電路 方向轉一轉令到佢係過左半個圈之後產生的反方向電流, 又轉番去本來果個方向。而ac發電機並冇呢個裝置,令佢產生既電流每半個圈就會轉一次方向。wikipedia入面講既野你可以睇下。但似乎入面中文就欠奉…http://en.wikipedia.org/wiki/Electrical_generator講到commutator既頁面http://en.wikipedia.org/wiki/Commutator_(electric)

AC出交流電
DC出直流電