例句與造句

1. A pulsating direct current may change in value, " i . e ., " be always present but at different levels, or it may be interrupted completely.
2. An AM radio signal can be demodulated by rectifying it, removing the radio frequency pulses on one side of the carrier, converting it from alternating current ( AC ) to a pulsating direct current ( DC ).
3. William Sturgeon built an electric motor in 1832 and invented the commutator, a ring of metal-bristled brushes which allow the spinning armature to maintain contact with the electric current and changed the alternating current to a pulsating direct current.
4. It's difficult to find pulsating direct current in a sentence. 用pulsating direct current造句挺難的