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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?

    Thanks--
     
  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

    sophiecentaur

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    Gold Member

    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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