1.
To reverse the direction of(an alternating electric current)each half - cycle to produce a unidirectional current.
变换电流方向颠倒每一半周（交流电流的）方向，以产生单方向性电流
2.
The direction of conventional current flow is counterclockwise.
传统的电流方向是逆时针方向。
3.
"Conventionally, the direction of electric current is that of the flow of the positive ions."
为了表示电流总的作用,通常取正载荷子的流动方向为电流方向。
4.
The current is in the same direction as the motion of the positive particles.
电流方向与带正电的粒子运动方面相同。
5.
The current flowing in one direction is called direct current .
沿着一个方向流动的电流叫做直流电。
6.
Direct current flows in one direction only. Alternating current flows first in one direction and then in the other.
直流电流仅向一个方向流动,而交流电流则先向一个方阿流动,继而又向另一个方向流动
7.
By AC it is meant that the current is flowing first in one direction and then back again.
交流电是指电流先流向一个方向，然后反方向流动。
8.
an electric current that reverses direction sinusoidally.
正弦地改变方向的电流。
9.
The difference between a direct and an alternating current is that a direct current always flows in one direction.
直流电和交流电的区别在于直流电总是向一个方向流动。
10.
energize a battery by passing a current through it in the direction opposite to discharge.
通过电流朝与放电相反的方向流动给电池充电。
11.
A direct current is a current flowing always in the same direction.
直流电是一种总是沿同一方向流动的电流。
12.
The rectifier lets current flow into the battery only when A.C. surges in the direction of the arrow.
只有当交流电流沿箭头方向急冲时，整流器才允许电流流入电池组。
13.
an electric current that flows in one direction steadily.
一直稳定地沿一个方向流动的电流。
14.
A diode rectifies alternating current.
电流在二极管中只朝单方向流动。
15.
It has been proved that induced voltage causes a current to flow in opposition to the force producing it.
已经证明，感应电压使电流的方向与产生电流的磁场力方向相反。
16.
The direction of the current was decided before electrons were discovered.
电流的方向在发现电子之前便已确定。
17.
The direction of the current is decide before electron is discover.
电子被发现前,电流的方向就被确定了。
18.
(electricity) of a current flowing in one direction only; not alternating.
（电学）只沿着一个方向的电流；没有交替。