Section outline

  • General

    Collapse all Expand all

  • 直接的和交替的当前

    A hand is pressing a switch next to an electrical outlet with a plug.

    To use an electric appliance, you have to plug it into an outlet unless it has batteries. This may be all you need to know in order to use electric current . But did you ever wonder what electric current is or how it flows through wires inside the walls of your home? Electric current is a continuous flow of electric charges. The charges may flow in just one direction, or they may keep reversing direction. 
    ::要使用电动电器,你必须将其插入一个出口,除非有电池。这可能是你使用电流需要知道的。但是,你是否曾想过电流是什么,或者电流是如何通过你家墙内的电线流动的?电流是电电流的不断流动。电流可能只是向一个方向流动,或者它们可能一直向相反的方向流动。

    Direct Current
    ::直接直接当期

    When current flows in just one direction, it is called direct current (DC) . The diagram below shows how direct current flows through a simple . An example of direct current is the current that flows through a battery-powered flashlight. In addition to batteries, solar cells and fuel cells can also provide direct current.
    ::当当前流向一个方向时,它被称为直接流(DC)。下图显示流流如何通过一个简单的流。直接流的一个实例是电流通过电池驱动的手电筒流。除了电池外,太阳能电池和燃料电池也可以提供直接流。

    Ddirect current flow in a simple circuit with a battery.

    Alternating Current
    ::互换当前

    When current keeps reversing direction, it is called alternating current (AC) . You can see how it works in the two diagrams below. The current that comes from a power plant and supplies electricity to homes and businesses is alternating current. The current changes direction 60 times per second. It happens so quickly that the light bulb doesn’t have a chance to stop glowing when the reversals occur.
    ::当电流保持逆向时,它被称为交替电流(AC ) 。 您可以在下面的两张图表中看到它是如何运作的。 电流来自电厂,为家庭和企业供电,电流是交替的。 电流每秒改变方向60倍。 电流发生得太快,当电灯泡发生逆向时,灯泡没有机会停止发光。

    Diagrams showing alternating current direction changes in a power system for electricity supply.

    Q: Which type of current flows through the wires in your home?
    ::问题:什么类型的流动流流通过你家里的电线?

    A: Alternating current from a power plant flows through the wires in a home.
    ::A:电厂的电流通过家里的电线流动而变化。

    Summary
    ::摘要

    • Direct current (DC) keeps flowing in just one direction. Batteries provide direct current.
      ::直接电流(DC)仅向一个方向流动,电池提供直接电流。
    • Alternating current (AC) keeps reversing direction. Power plants provide alternating current.
      ::交替电流(AC)不断逆向。 电厂提供交替电流 。

    Review
    ::回顾

    1. Compare and contrast direct and alternating current.
      ::比较和对比直接和交替的洋流。