1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: Electric field across a parallel plate capacitor

  1. Mar 22, 2009 #1

    If I had a potential source (V) , a resistor R, and a parallel plate capacitor,

    would the Electric field across the capacitor become

    E = (V - IR)/L

    L = distance between capacitor

    or would the electric field simply become E = V/L


    thank you!!
  2. jcsd
  3. Mar 22, 2009 #2


    User Avatar
    Homework Helper

    How is the circuit set up? Your E = (V - IR)/L would be correct for a purely series circuit. But the current would be zero (or quickly become zero as the capacitor charges) so your second formula is then correct.
  4. Mar 22, 2009 #3


    User Avatar
    Homework Helper

    That very much depends on whether the resistor is in series or in || with the capacitor doesn't it?
  5. Mar 26, 2009 #4
    Ah ic, oh okay I understand now.

    so if in series,
    clearly initially it is

    E = (V-IR) /L
    but after the capcitor is fully charged then E = V/L

    however if in parallel from the start then

    E = V/L, always

    would this be correct?
  6. Mar 26, 2009 #5


    User Avatar
    Homework Helper

    If the V, R and C are all in parallel then they all have the same potential V.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook