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Homework Help: Theory behind investigating factors affecting inductance

  1. Apr 12, 2010 #1
    1. The problem statement, all variables and given/known data


    I am currently doing an investigation to study the factors affecting inductance. The three variables i am using are the number of turns on the coil, the material of the core of the coil and putting 2 cores in series/parallel to see how this affects the inductance in a d.c circuit.

    now i have done experiments for each whereby i measured V across inductor to allow me to work out I and therefore see the affect on L in L= -ε ÷(dI/dt)

    i just have a couple of questions though. first of all, am i right in saying that my value for ε (self-induced emf) will the same as the supply voltage?

    also, i am requesting some help with my theory work deriving the equation for each variable. i have done the theory for changing number of turns by showing how it affects the magnetic flux produced. but im having problems with the other 2 variables i.e. changing the core/parallel & series circuits; where/what equation with should i start?

    Any help hugely appreciated.
    Thanks for your time.
  2. jcsd
  3. Apr 12, 2010 #2


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    Science Advisor
    Gold Member

    You don't say what kind of physics/engineering background you have. Have you seen the equations for series and parallel inductance, including mutual inductance? For iron-cored solenoids?

    One immediate question: what is dI/dt in your equation, given that you are using DC?
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