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How current relates to capacitance

  1. Jul 31, 2013 #1
    Hi all,

    I have a simple circuit with a battery, resistor, and finally, the capacitor.

    Am I correct in saying that adding additional resistors will increase the charging time, because adding resistors will decrease the overall current?

  2. jcsd
  3. Jul 31, 2013 #2
    Basically....yes.....with the information you have provided!!

    PS.....unless you connect the resistors in parallel
  4. Jul 31, 2013 #3


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    It is really far more fruitful to describe what happens using Maths.
    We assume the three are in series. The time constant (time for the voltage across the Resistor to go to 1/e of any initial value) is given by RC. It's an Exponential variation. As the Voltage decreases exponentially, so does the current flowing because I = V/R.
  5. Aug 1, 2013 #4
    A more direct way for you to consider the time constant is that RC is the time taken for the CURRENT in the series circuit to decrease to 1/e of its initial value.
    (your question related to the current)
    T = RC so larger R means longer time for the current to decrease.
    Increasing R decreases the current which increases the time to charge the capacitor.
    Last edited: Aug 2, 2013
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