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Homework Help: Energy dissipated in RC circuits

  1. Mar 21, 2013 #1
    1. You are investigating how energy is transferred in circuits with batteries, resistors, and a capacitor. First you take an uncharged capacitor and connect it in a simple series circuit with a resistor and a battery. You wait for the circuit to reach a steady state. After a steady state is reached, you disconnect the capacitor. You then connect the capacitor in a simple circuit with a resistor (of different resistance) only (no battery) and wait for this second circuit to reach a new steady state. Your job is to find algebraic expressions that represent the total energy dissipated by each resistor.

    2. Relevant equations

    t=0, deltaVc=0
    t→∞ deltaVc=Vo
    deltaV =Q/C ⇔Q=C*deltaVc=CVo
  2. jcsd
  3. Mar 21, 2013 #2


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    Do you know the formula for the stored energy in a charged capacitor? If not, can you derive it, using the voltage (=energy per new charge) as function of the charge at the capacitor?
  4. Mar 21, 2013 #3

    rude man

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    Total energy dissipated in each resistor is ∫i2R dt from 0 to ∞.

    What is the current i(t) while the capacitor charges?

    What is i(t) while the capacitor discharges?
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