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 and time constant

  1. Jul 22, 2009 #1
    1. The problem statement, all variables and given/known data

    Three identical capacitors are connected with a resistor in two different ways. When they are connected as in part A of the drawing, the time constant to charge up this circuit is .34s. What is the time constant when they are connected with the same resistor as in part B?

    2. Relevant equations

    t = RC

    3. The attempt at a solution

    I think the first thing I would need to do is find the capacitance of the first circuit, but I don't know how to do that since I only know the time.

    Attached Files:

  2. jcsd
  3. Jul 23, 2009 #2


    User Avatar
    Homework Helper
    Gold Member

    Can you find an expression for the capacitance, C, using the time constant given?

    HINT: Solve for C in terms of [itex]\tau[/itex] using info from circuit A. Then use that expression for C to solve for the time constant in circuit B.
  4. Jul 23, 2009 #3


    User Avatar
    Homework Helper

    Find the equivalent capacitance in the circuit A and B using series and parallel combination formula.
    Then write two equations for time constant, one for A and other for B.
    From them find the time constant of B
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: RC Circuit and time constant