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: Mutual inductance / equivalent inductor

  1. Oct 31, 2016 #1
    1. The problem statement, all variables and given/known data

    2. Relevant equations
    See if you can show that L##_1## and L##_2## as in (a) can be replaced by the equivalent inductor L##_{eq}## as in (b):

    $$L_{eq} = \frac {L_1 L_2 - M^2 } {L_1 + L_2 - 2M }
    3. The attempt at a solution
    Um, I don't really know where to start because I don't really understand what the question is asking. Am I supposed to provide some 'proof' in algebraic form? Thus I don't know the form that the answer should take, as in what equals what.

    A gentle nudge would get me moving :)
  2. jcsd
  3. Oct 31, 2016 #2


    User Avatar

    Staff: Mentor

    Just like reducing a resistor network to a single equivalent resistance, they want you to reduce the inductor network to a single equivalent inductor. The tricky bit is handling the mutual inductance. How you go about it is up to you, but consider driving the circuit with ac test voltage V and finding the resulting current it supplies. Then compare to the expression for the current if the load was just a single inductor Leq.
  4. Oct 31, 2016 #3
    Thank you. I shall post my attempt for scrutiny!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted