RMS Voltage for a Triangular waveform

Discussion in 'Homework Help' started by Larry Makanza, Nov 19, 2010.

  1. Larry Makanza

    Thread Starter New Member

    Nov 19, 2010
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    0
    Is there a standard formula for calculating the RMS value of a triangular waveform?
     
  2. bertus

    Administrator

    Apr 5, 2008
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  3. someonesdad

    Senior Member

    Jul 7, 2009
    1,585
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    If a numerical result is suitable, here's a python script that will calculate the RMS value of a waveform. You need the matplotlib and numpy libraries; they can be gotten from the SciPy website.

    Code ( (Unknown Language)):
    1.  
    2. from pylab import *
    3.  
    4. dist, numpoints = 1.0, 100
    5. x = arange(0, dist, dist/numpoints)
    6. ypos, yneg = x, -x + 1
    7. x = arange(0, 4*dist, dist/numpoints)
    8. y = concatenate((ypos, yneg, yneg - 1, ypos - 1))
    9.  
    10. rms = sqrt(average(y*y))
    11.  
    12. plot(x, y)
    13. title("RMS value of a triangle wave")
    14. text(2.5, 0.7, "RMS = %.3g" % rms, fontsize=20)
    15. grid(True)
    16. show()
    17.  
    It produced the attached graph. It goes without saying that the method can calculate the RMS value of any waveform that you can write down a formula for. Of course, since it is using a sampled waveform, you'd want to increase the number of points to make sure you weren't seeing quantization errors.

    It's also a short step to using something like SciPy's Romberg integration routine to do a numerical integration of the function using the definition of the RMS value. This would be a more efficient way to get a high precision answer. But for most engineering problems, 2 or 3 significant figures are fine and are most easily gotten by the first approach.
     
    • rms.png
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  4. Larry Makanza

    Thread Starter New Member

    Nov 19, 2010
    3
    0
    Just want to say thanks to Bertus and Someonesdad for your replies. It was a great help.

    Larry Makanza
     
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