Rectified mean value [Square waves]

Discussion in 'Homework Help' started by Majkul, Mar 13, 2014.

  1. Majkul

    Thread Starter New Member

    Mar 13, 2014
    2
    0
    Hello!

    I have problem solving the rectified mean value of these two square waves.

    [​IMG]

    I have got the U_DC (mean value) to 1,25V (first wave) and 2,25V (second wave). I´m not really sure if those are the correct values though.

    I need help to solve the rectified mean value of both waves. This is the integral to use:
    [​IMG]

    Can someone guide me through this integral so I get the RMV at the end?

    Regards
    Majkul
     
  2. Papabravo

    Expert

    Feb 24, 2006
    10,143
    1,790
    What is the time coordinate of the rising edges? It is not labeled and I would not want to assume a value for it.
    Your notation for the integral makes no sense because you have the same function under the integral that you have on the left hand side. Integrals don't work that way. Maybe the LHS is a number resulting from the evaluation of the definite integral. Is that what you mean?
     
  3. Majkul

    Thread Starter New Member

    Mar 13, 2014
    2
    0
    I´m novice when it comes to integrals so I don´t really know how to use them. The time label on the top (5V) is 0,25ms and in the bottom (0V) it´s 0,75ms.
     
  4. Papabravo

    Expert

    Feb 24, 2006
    10,143
    1,790
    I agree with 0,25 ms for the rising edge, but the trailing edge is at 0,5 ms -- NOT 0,75 ms.

    WRT to the integral: if you can't tell us what you think it means then how can we help you? The way they work is that you can't have the identical function on the left hand side AND inside the integral unless it is an exponential function. Clean up the notation so that it indicates a numerical value of the definite integral on the left hand side and a function of t inside the integral on the right hand side. Novice or not precise notation is not everything in Mathematics and Engineering -- IT IS THE ONLY THING!
     
  5. WBahn

    Moderator

    Mar 31, 2012
    17,743
    4,795
    Can you write an expression for u(t) for your two waveforms?

    Can you then write an expression for |u(t)| for your two waveforms?

    Can you then plug that into the integral formula by breaking it into more than one integrals with appropriate limits?

    Show your attempt at each of these and, depending on how far you get, we can help get you back on track (if necessary) and moving on.
     
  6. MrChips

    Moderator

    Oct 2, 2009
    12,441
    3,361
    What is an integral?
    Are you aware that an integral is a summation?

    Think of a histogram or bar chart. When you calculate the integral you are summing the values in each column. The result is also the area under the graph.
     
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