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Homework Help: Voltage across parallel switches

  1. May 28, 2008 #1

    The 300 micro-Farad capacitor in the figure is initially charged to 110 V , the 1200 micro-Farad capacitor is uncharged, and the switches are both open. What is the maximum voltage to which you can charge the 1200 micro-Farad capacitor by the proper closing and opening of the two switches?

    I know that electric potential (aka voltage) will increase if the current decreases, and that the most rapid way to decrease current is to open a switch that has been closed for a long time. So I assume the best plan is to close switch 1, wait until the current is at its max, then close switch 2 and open switch 1. Does this sound reasonable?

    I also am not sure how to calculate this transfer of current, however. Should I use the equation for potential difference deltaV = -L(dI/dt) ? I can equate L = R(tau) to get
    deltaV = -LR(tau) * (dI/dt), but I am unsure where to go from there, because I am not sure how voltage is transferred between switches.

    I appreciate your time.
  2. jcsd
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