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Homework Help: How can i put the polaritiy of E thevenin's ?

  1. Nov 20, 2013 #1
    Hello guys ..

    i need your help with something

    in this photo i understand the way to calculate R thevenin's and the way to calculate E thevenin's

    but i couldn't understand

    why did we put the polarity in this way ??

    i mean why can't we put switch the polarity of the battery ??


    thanks guys :))
  2. jcsd
  3. Nov 20, 2013 #2


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    Staff: Mentor

    Because solving the potential dividers shows that Vb is greater (more positive) than Va.

    If you want to turn the battery symbol around you can do so by specifying the battery voltage to be -6V rather than +6V. Technically this is allowed, but it may bother some who insist that a battery's positive terminal really should be positive with respect to its negative terminal :smile:
  4. Nov 20, 2013 #3
    okay that's mean that we can turn the symbol of the battery if we turned "a" and "b" in the other side ??
    i mean if we put b in the upper right side and a in the lower right side ?? :)
  5. Nov 20, 2013 #4


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    Staff: Mentor

    Sure, if you also move the ground symbol to the top so it stays connected to b.
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