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Homework Help: How does current move

  1. Apr 18, 2010 #1
    Hi, I was wondering am I correct to say that in a circuit, more current will flow in the path where the resistance is the least? If an inductor and a resistor are connected in parallel to a battery with the inductor initially uncharged. The current passing through the inductor will rise slowly to a certain value correct? But how do we find the current passing through the inductor? I tried using Kirchoff's law and got these three equations-
    I2R=E
    I3+I2=I1
    -I2R+L(dI3/dt)=0

    After some algebra I got -I1R+I3R+L(dI3/dt)=0 which gives me I3(t)=-I1[1-e-(Rt/L)]. Is this correct? This equation suggests after the inductor is charged up the current will not flow through the resistor?
     

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    Last edited: Apr 18, 2010
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  3. Apr 18, 2010 #2

    Matterwave

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    Science Advisor
    Gold Member

    Because of conservation of charge, you can't have current moving at different rates across a resistor and an inductor in a series. Currents can only differ if the circuit is in parallel (or for a capacitor...since capacitors store charge - currents don't actually move across capacitors).
     
  4. Apr 18, 2010 #3
    Sorry I meant to say parallel circuit.
     
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