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Average power and diodes.

  1. Apr 12, 2008 #1
    [SOLVED] Average power and diodes.


    I have this question. If a diode were connected to a circuit with an alternating current and there was a resistor was connected to it, will the average power change? For example, if we take the following values,

    V max = 6.0 V
    Resistance = 100 ohms,

    the Average power will be 0.18 W and the max power 0.36W. When we plot the graph with respect to power dissipated by the resistor with a diode connected, we get a sinusoidal graph with it's second half cycle at a null value and it's first half at a peak value of 3.6W (assuming that the diode is forward biased at the start).

    I'm not very sure how to calculate max power using graphs; but is the average power still 0.18W?

    I thank you for your help in advance.
  2. jcsd
  3. Apr 12, 2008 #2
    Anyway, I think I solved it. Thanking the Half Rectified wave to be H and the original unrectified full wave to be F, the mean power of the half rectified wave should be half that of the full wave.


    <[tex]P_{H}[/tex]> = 1/2<[tex]P_{F}[/tex]>
    = 1/2([tex]P_{o}[/tex]/2)
    = 1/4 [tex]P_{o}[/tex]

    where [tex]P_{o}[/tex] is the max power.
    Last edited: Apr 12, 2008
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