I have op amp, RLC, Resistor network, 8 questions, please help me :(

Discussion in 'Homework Help' started by Mechanicalengineerr, May 15, 2015.

  1. Mechanicalengineerr

    Thread Starter New Member

    May 15, 2015
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    I have to finish this homework in 2 days. If i can solve this question, i ll pass circuit theory. Anyone can help me? :(

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  2. joeyd999

    AAC Fanatic!

    Jun 6, 2011
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    You've already wasted 10 minutes waiting for someone to give you the answers.
     
  3. OBW0549

    Well-Known Member

    Mar 2, 2015
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    Those are REALLY easy problems! C'mon, you can do it!!!
     
  4. WBahn

    Moderator

    Mar 31, 2012
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    And if you can't even make enough of an effort to show an attempt to solve YOUR homework, then perhaps you don't deserve to pass circuit theory.
     
    panic mode likes this.
  5. MrAl

    Well-Known Member

    Jun 17, 2014
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    Hi,

    What exactly are you having trouble with?
     
  6. Mechanicalengineerr

    Thread Starter New Member

    May 15, 2015
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    I m trying solve questions. I ll load images. Then can u say true or false?
     
  7. WBahn

    Moderator

    Mar 31, 2012
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    We'll do more than that. If you show an honest effort to solve your work, we will look it over and point out errors you have made and ask leading questions to help steer you into figuring out how to correct them and move forward.

    But, PLEASE, one problem at a time.

    Let's start with that first one, shall we?
     
  8. Mechanicalengineerr

    Thread Starter New Member

    May 15, 2015
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    Yes you are right. I have to show an honest effort but i couldnt solve. I ll load first one. i think it is false :/

    20150516_145238s.jpg
     
  9. 0Wafi0

    New Member

    May 15, 2015
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    for the first question I'd go with mesh analysis
     
  10. Mechanicalengineerr

    Thread Starter New Member

    May 15, 2015
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    Hmm my answer is false, isnt it? i ll try mesh analysis
     
  11. WBahn

    Moderator

    Mar 31, 2012
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    You haven't shown much work. Yes, your solution is incorrect, but we can't tell where you went wrong from what you presented. In going from your top diagram to your bottom diagram, how did you determine that the equivalent resistance of those three resistors we 3kΩ. That's incorrect and you did it wrong, but unless you reveal the reasoning you used, we can't tell why you did it wrong and therefore can't help you correct your reasoning process. If you are adding them because resistors in series add, then you need to ask yourself what is required for two (or three, in this case) resistors to be in series.
     
  12. Mechanicalengineerr

    Thread Starter New Member

    May 15, 2015
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    Now, where is wrong? :/
     
  13. Mechanicalengineerr

    Thread Starter New Member

    May 15, 2015
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    Okey. You cant tell. You are really helpful :D
     
  14. joeyd999

    AAC Fanatic!

    Jun 6, 2011
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    Does your answer make sense?
     
  15. WBahn

    Moderator

    Mar 31, 2012
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    What, you post your work and because I haven't come back in eleven minutes you post that?

    Just what do you expect?

    Look at your lower right diagram. It shows a 1kΩ resistor going from Point B to Point A and then a 1kΩ resistor going from Point B to Point C. Which 1kΩ resistor in the original diagram is connected between points B and C?

    The value you are trying to find, Vo, is the voltage between points B and C. So in your lower right diagram, where are points B and C? You MUST keep those as identifiable points in your circuit reductions.

    Then you have Req calculated twice, but you never bother to define what Req even is! We are NOT mind readers.
     
  16. panic mode

    Senior Member

    Oct 10, 2011
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    the only source is 10V and all other components are resistors. does it make sense that Vo=25V (greater than source)?
     
  17. Mechanicalengineerr

    Thread Starter New Member

    May 15, 2015
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    If i can understand circuit theory, i didnt ask you. Why did you surprise??? I didnt know how to solve, so i m here.
     
  18. panic mode

    Senior Member

    Oct 10, 2011
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    you computed Req[A-C]=666Ohm correctly but then didn't use it correctly in next step:
    Note Vo=Vbc and not Vo=Vac

    then there is a mistake in computing Req (same label?) again, as if 666 and 1000 ohms were in parallel (!?).
     
  19. WBahn

    Moderator

    Mar 31, 2012
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    But we are having a very hard time getting a grasp on just how much you don't know.

    You have eight problems that roughly span an entire Circuits I course, including op amp circuits and magnetically coupled circuits yet you don't have a grasp on what it takes for two resistors to be in parallel or series. You also don't seem to be able to ask if it makes since for an purely resistive circuit powered by a 10V source to produce a 25V output.

    Frankly, it seems like you've dug yourself a pretty deep hole. We are willing to work with you to help you climb out of it, but it is going to involve a lot of work on your part, something which present evidence suggests you have not been willing to devote too much of to learning this stuff.
     
  20. Mechanicalengineerr

    Thread Starter New Member

    May 15, 2015
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    Okey, i found answer. Thank you for your help :)
     
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