Voltage across each resistor in a circuit with both Parallel and Series Connections

Discussion in 'Homework Help' started by FightingMyInnerFolly, Jul 31, 2008.

  1. FightingMyInnerFolly

    Thread Starter New Member

    Jul 31, 2008
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    Hello:

    I know this is probably simpler or somehow different than I am seeing it, but I do not have complete confidence in how to answer to the following question:

    Please refer to the attached figure for this problem.

    Using the information given in the figure, find (a) the equivalent resistance and the current through the independent voltage source, (b) the voltage across each resistor, (c) the current through each resistor, (d) the energy per second wasted by each resistor, and (e) the energy per second wasted by the equivalent resistance. Note that VAB =50 volts.

    Now, I have figured out part (a) [I found Req =5 ohms and Ieq =10 amperes]and I feel confident about how I arrived at my answers. However, part (b) I feel like I do not know how to answer confidently. This may have been an incorrect assumption, but since I could not figure out part (b) I have not attempted any of the subsequent parts yet.

    Please help me if you would: I just feel incredibly uncertain about how to figure out this sort of thing. Its seems there are no similar examples in my Physics textbook (or anywhere else I could find).
     
  2. Wendy

    Moderator

    Mar 24, 2008
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    OK, the last 2 resistors can be merged as parallel. The AAC eBook has a section that deal specifically with the resultant schematic, I'll look it up and post it.

    BTW, it helps to have designators on the resistors so we can be specific when we're talking about an individual.

    ************************

    Check this section out, matter of fact the whole volume is a good read.

    http://www.allaboutcircuits.com/vol_1/chpt_10/13.html
     
  3. FightingMyInnerFolly

    Thread Starter New Member

    Jul 31, 2008
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    0
    Thanks for taking the time to read and reply to my post, I greatly appreciate it. Also, thank-you for pointing me in the right direction with the link.
    After looking at the page of which you sent me the link, I just want to verify something: in Physics (standard University Calculus based Physics second semester), as opposed to electrical engineering, are different methods employed for such problems? If so, I believe I have found one of my sources of confusion - the convoluted way my Physics textbook explains this sort of scenario.
    Regardless, that link was very insightful, so thanks again!
     
  4. Wendy

    Moderator

    Mar 24, 2008
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    Not sure, but Engineering in general is more interested in arriving at the right answer than the technique used. If you read the text in the book they mention how they prove the theorem is quite convoluted, then show the end result.
     
  5. The Electrician

    AAC Fanatic!

    Oct 9, 2007
    2,281
    326
    Since they want the voltage across and the current through each resistor, you're going to have to solve the complete network. Just finding the equivalent resistance won't answer all the parts of the problem.

    Read up on the nodal method:
    http://www.allaboutcircuits.com/vol_1/chpt_10/4.html
     
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