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Significance of Average value of a AC signal

  1. Feb 26, 2008 #1
    [SOLVED] Significance of Average value of a AC signal

    I would like to know the significance of average value in a AC circuit. Lets consider a sinusoidal ac source with only a resistor in the circuit. The rms value of voltage and current indicate the equivalent DC value which would dissipate the same heat in the same circuit. So on similar terms what will the average value signify ?

  2. jcsd
  3. Feb 26, 2008 #2


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    The average value of a signal is the DC component of the signal. In a sinusoidal wave the average value is zero.
  4. Feb 26, 2008 #3
    ofcourse, but what will it be if only magnitude is considered ? . What will the average value represent in a full wave rectified signal ?
    It certainly does not represent DC value as rms value does that.
  5. Feb 26, 2008 #4


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    Staff: Mentor

    The average value is just the DC offset of the AC signal. A sine wave signal can have a DC offset. For example, like this:

    v(t) = 2.5V + 2.5V cos(wt)
  6. Feb 26, 2008 #5
    This has a good explanation of both and also a comparison and why some applications use RMS and others use just average

  7. Feb 26, 2008 #6


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    No, rms represents the value of a DC source that would output the same power as the sinusoidal source.
    A rectified wave can be thought as the combination of a DC source (the mean value) and an infinite number of sinusoids with frequencies that are the harmonics of the original sinusoid. The Fourier series of the wave shows exactly this.
  8. Feb 27, 2008 #7
    thanks a lot guys.

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