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!

Signs of emf inducted and autoinducted

  1. Sep 24, 2013 #1
    1. The problem statement, all variables and given/known data
    I'm a little confused.. When I write the equation of the circuit, do I have to keep the signs of the induced emf and self-inductance opposite?

    I'll try to explain better my doubt:
    Consider a coil that has resistance R and inductance L. Running a current will give rise to both an induced emf and self-inductance, and the situation is:

    induced emf= -k

    self-inductance= [itex]-L \frac{dI}{dt}[/itex]

    Now, my question is: the equation of the circuit is given by:

    [itex]-k -L \frac{dI}{dt}=RI[/itex]

    or by

    [itex]k -L \frac{dI}{dt}=RI[/itex] ?


    3. The attempt at a solution
    I think that the self-inducted emf fights the inducted emf so, self-inducted emf and inducted emf have ho have different signs and so the equation of the circuit is given by
    [itex]k -L \frac{dI}{dt}=RI[/itex]. But I'm not sure. Could you help me?
     
  2. jcsd
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted



Similar Discussions: Signs of emf inducted and autoinducted
  1. Amplitude of emf (Replies: 1)

  2. Motional EMF (Replies: 1)

  3. Difference in sign (Replies: 1)

  4. EMF Formula (Replies: 1)

Loading...