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Homework Help: RC Circuits HELP!

  1. Sep 12, 2010 #1
    1. The problem statement, all variables and given/known data

    Find the voltage across a capacitor in an RC Circuit, using [V]_{}[/c] (0) = 1, [V]_{}[/i] n(t)=t.

    2. Relevant equations
    dV/dt = (1/RC)(V)=(1/RC)([V]_{}[/in])

    3. The attempt at a solution
    New to this site: I honestly don't know where to start. Done well in Calculus. Feel DifEq is like a breed of its own..aha

    I know you have to use this type of an equation: VC = V0(1− e−t /τ ) where τ = RC and V0 is the initial voltage
  2. jcsd
  3. Sep 12, 2010 #2
  4. Sep 12, 2010 #3
    I'm a little confused by your equations..

    In general the voltage across a series RC circuit will decay exponentially, on a time constant determined by the value of RC.

    The voltage across a resistor is:

    [tex]V_R = IR = R\frac{dQ}{dt}[/tex]

    The voltage across a capacitor is:

    [tex]V_C = Q/C[/tex]

    Knowing this, you should be able to set up a simple differential equation which will provide the answer you desire.
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