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Homework Help: Basic RC circuit

  1. Mar 22, 2010 #1
    1. The problem statement, all variables and given/known data

    The capacitor in the circuit has 537 μC of charge on it at t=0. The resistor is 1,923 Ohms, and the capacitor is 1,251 microFarads

    How long will it take for the charge on the capacitor to drop to 195 μC?

    Please use only SI (metric) system units in your answer!

    2. Relevant equations

    ?? I do not know.

    3. The attempt at a solution

    I am so lost.

    Attached Files:

  2. jcsd
  3. Mar 22, 2010 #2
    Use the time constant equation for a drop:

    Qf= Qo e^-t/T, where T is the time constant, or R x C. You know or can find all of these variables, and solve the equation for t. Make sure you convert your C to Farads.

    I think this is correct. I'm only an undergrad student, but just had an exam containing RC circuits and did really well.
  4. Mar 22, 2010 #3
    Thank you. This did work. It is an online assignment so I can check my answer right away.
  5. Mar 22, 2010 #4
    Cool. Glad I actually did learn something in Physics class lol.
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