Energy Dissipation Circuit

Discussion in 'Homework Help' started by jegues, Sep 15, 2012.

  1. jegues

    Thread Starter Well-Known Member

    Sep 13, 2010
    See figures attached for question and my work.

    I'm having trouble finding the peak energy in the inductor, and the average power supplied by the source. For the latter, how do I go about finding the average current?

    Thanks again!
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  2. WBahn


    Mar 31, 2012
    The contrast in the image is too poor for my weak eyes to make out. But, without even looking at the figure, I can guess one of the things that could trip you up. In general, you can't use average current to calculate average power. But there are a number of ways to go about it. For instance, consider the following questions:

    Q1) Given the peak current in the inductor just before the transistor switch is shutoff, what is the peak energy in the inductor? (Hint: What is the relatinship between the current in an inductor and the energy stored in it's magnetic field?)

    Q2) If the L/R time constant is << than the off period, what will become of all of the energy in the inductor each time the transistor switch is shut off?

    Q3) Given the answer to Q1, how much energy is the source providing to the circuit each complete period? What, then, is the average power supplied by the source?