Connect with us

Current calculation of passive RLC network using DE

Discussion in 'Electronic Basics' started by Mike, Jun 25, 2007.

Scroll to continue with content
  1. Mike

    Mike Guest

    Hi Experts,

    Not entirely sure if this posting is more appropriate in the symbolic.math
    group or this group, but since it is a current calculation, I'm thinking its
    fine to post here as well. I am trying to figure out how to solve the
    following problem relating to a passive circuit in a closed loop described
    by the following differential

    L*dI/dt + R*I = Eo (intial Differential Equation)

    The problem is to solve the equation when an initial current Io is flowing
    and a constant emf Eo is impressed on the circuit at time t =0. Using
    variables separation, I can arrive at:

    dI / (Eo - R*I) = 1/L*dt

    and then I integrate both sides:

    -log(Eo-R*I)/R = R/L*t + C1 // note - only 1 log term

    The published solution using the initial condition I(0) = Io is:

    log(Eo-R*I) = R/L*t + log(Eo - R*Io) // note the 2nd log term

    I am guessing that the additional log term is obtained by solving for the
    constant C1, but how ?

    Any input would be greatly appreciated!

Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day