1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

RC Circuit charging question

  1. Dec 2, 2015 #1
    1. The problem statement, all variables and given/known data
    .
    Switch http://edugen.wileyplus.com/edugen/courses/crs7165/halliday9781118230725/c27/math/math152.gif in Fig. 27-63 is closed at time http://edugen.wileyplus.com/edugen/courses/crs7165/halliday9781118230725/c27/math/math164.gif, to begin charging an initially uncharged capacitor of capacitance 15 microfarads through a resistor of resistance 20 ohms. At what time is the potential across the capacitor equal to that across the resistor?
    http://edugen.wileyplus.com/edugen/courses/crs7165/halliday9781118230725/c27/image_n/w1548-nn.png
    Figure 27-63
    Problems 57 and 96

    2. Relevant equations
    v=vmax(1-e^-(t/RC))
    V=iR
    i=imax(e^-(t/RC))


    3. The attempt at a solution
    The answer winds up being .208 ms. so I am just looking for an answer. I want to know how to solve this. I tried using ohms law to figure out what the voltage is across R but of course that was a dead end because the emf is not given. next I tried iR=vmax(1-e^-t/RC). Again a dead end. Also I know that when the capacitor is fully charged the current is zero, hence the voltage across R will also be zero but I couldnt figure out how to implement that knowledge into a solution. Any help would be greatly appreciated.
     

    Attached Files:

    Last edited: Dec 2, 2015
  2. jcsd
  3. Dec 2, 2015 #2

    SteamKing

    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    None of the links to your figures are working.
     
  4. Dec 2, 2015 #3
    I just uploaded another pic. In case that one doesnt work, the circuit is just an RC series circuit with a battery and a switch.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: RC Circuit charging question
  1. RC circuit (Replies: 5)

Loading...