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To solve ISRO paper, Can I post my doubt questions here in this thread

  1. Mar 13, 2013 #1
    I have a multiple choice question paper from ISRO 2012.

    http://www.isro.org/pdf/EC-2012.pdf [Broken]

    Can I post doubtful questions in this thread. Is there someone to help me.

    -Devanand T
     
    Last edited by a moderator: May 6, 2017
  2. jcsd
  3. Mar 13, 2013 #2

    berkeman

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    Staff: Mentor

    I think as long as you post about just one question at a time, and list the Relevant Equations and show your sincere Attempt at a Solution, it should be okay to do for now.
     
    Last edited by a moderator: May 6, 2017
  4. Mar 13, 2013 #3
    Thank you sir, I will do that..
     
  5. Mar 13, 2013 #4

    berkeman

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    Which question do you want to tackle first?
     
  6. Mar 13, 2013 #5
    The circuit diagram is shown in the attached file..q18

    The question 18 is regarding harmonics of current wave in the ac circuit having diodes.

    My answer if option (a) , any mistake here..
     

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  7. Mar 14, 2013 #6

    NascentOxygen

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    I don't think we can assume ideal or idealized diodes here, for the simple reason that if the source is an ideal sinusoid, and the diodes were to drop a fixed 0.6V, then where does the remainder of the voltage disappear?

    So I picture operation over the diode's exponential curve (which extends to infinity), and giving rise to a distorted alternating current (perhaps missing a portion around the zero crossings).

    Being a distorted sinewave, it contains harmonics.
     
  8. Mar 14, 2013 #7
    Ok thankyou sir , will come with other doubts in the same paper..
     
  9. Mar 14, 2013 #8

    NascentOxygen

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    I haven't answered the question, apart from ruling out (a).
     
  10. Mar 14, 2013 #9
  11. Mar 14, 2013 #10
    As diode is having a nonlinear behaviour can we say the output is like
    I = a + b v^1 + c v^2 + d v^3 + .............

    so will all harmonics come...
     
  12. Mar 14, 2013 #11

    NascentOxygen

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    I don't think so. I think you should try to sketch the expected current waveform.
     
  13. Mar 14, 2013 #12
    ok I will try.
     
  14. Mar 17, 2013 #13
    7th question

    Hi pf,
    Please see the attached figured , it is the 7th question.
     

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