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Find the power in the circuit

  1. Sep 14, 2011 #1

    My biggest issue is I don't know what to do with the ix
    So I really just need to know how to calculate power for C and E. Thank you!
  2. jcsd
  3. Sep 14, 2011 #2


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    Gold Member

    The ix current is given as 3A, but it is in the opposite direction, so we say ix = -3A.

    E is a Current Controlled Voltage Source (CCVS) which has the voltage across it depending on the current ix. We know ix = -3A so V(E) = 2 * ix = -6V.

    This doesn't make sense for the circuit though, as we need E = 6V for the law of conservation of energy not to be violated, so pretend E = 6V for your calculation.
    Last edited: Sep 14, 2011
  4. Sep 14, 2011 #3
    thank you!
  5. Sep 15, 2011 #4


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    Actually, I think you could ignore it! * :uhh:

    Simply because you know the current through each of the elements, and you know the magnitude of the voltage across each, so for each P=V.I

    Okay, you may not have been told the voltage across that rhombus-thing :smile:
    but the element in the centre has 10volts, and that on the right has 4volts, leaving (paying close attention to polarities) 6volts across the rhombus. (I must admit I didn't recognize it as a CCVS until Zryn pointed that out.)

    It's not clear whether you need to attach a + or - sign to each power calculation, to indicate whether a power source or sink. If in doubt, it won't hurt to do so.

    *you can do this in this case because there seems to have been more information provided on I's and V's than absolutely necessary
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