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AC versus DC

  1. Jul 29, 2011 #1
    What are the benefits of having Alternating current instead of direct current? i'm just wondering why we use AC instead of DC..
  2. jcsd
  3. Jul 29, 2011 #2


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    Did you try a search of the forum first? This question arises every few weeks and there are dozens and dozens of comments in the archives.
    But, to sum up:
    DC is what you can get from batteries and is good for powering electronic equipment. AC is by far the best form to generate high levels of power efficiently and it can be transformed to different voltages very easily - so it's good for distribution of large quantities of electrical power.
    Search the Electrical Engineering Forum.
  4. Jul 29, 2011 #3
    Politics of the era, and who was able to promote their version of generation. Historically.

    As for practical, this is such an open and general question that a discussion is beyond the scope of the limited space in this thread.
  5. Jul 30, 2011 #4
    The main difference is that in dc the electrons flow in one direction, like water through pipes. In AC the electrons keep moving back and forth.

    AC can take advantage of things like transformers, since they need a CHANGING magnetic field to work (and with AC the magnetic field oscillates with the back-forth motion of the electrons).

    A transformer allows you to trade current for voltage, and vice-versa. Since in power lines the higher the current, the less efficient they are, raising the voltage to stupidly high levels while lowering the current to stupidly low levels can increase their efficiency, letting you send power further away without losing it all by the time it gets there.
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