The inductor develops magnetic field around it to store the kinetic energy of the electrons into magnetic field, but i don't have a clue why does it opposes the change of current passing through it and how .. i know the Lenz's law but don't know the physics behind that..
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\$\begingroup\$ It's because it's storing energy, think about kinetic energy, if you want to stop, all that energy has to go somewhere, it doesn't want to stop easily, it wants to keep going. The flow of current in the inductor is exactly the same, you don't need any physics here, just a thought experiment, when something's moving, it want's to keep moving, or more precisely, it want's to stay as it was before, heavy rock wants to sit there, car rolling down hill wants to keep going. The direction and magnitude isn't important, things just want to stay as they are \$\endgroup\$– SamCommented May 5, 2016 at 7:10
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3 Answers
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The opposition to change in current is observed because the inductor is extracting power from the current and storing it as energy in the magnetic field.
So, if the current is increasing, the magnetic field will build up (which takes energy). This energy must come from the current and is extracted by causing a positive voltage across the inductor.
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2\$\begingroup\$ Key point, it's not the kinetic energy of the electrons that's transferred, it's their electrical potential energy. \$\endgroup\$ Commented May 5, 2016 at 3:58
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If I wanted to store some mechanical energy I could push a rock to the top of a hill. Easy to do? No, because the rock fights all the way until I stop pushing.
If you want to take energy out of one system and put it somewhere else, of course there's "opposition". You don't get energy for free.
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Natural systems tend to not like change, they want to keep equilibrium. An inductor is a classic example of a natural phenomenon which is this way. An inductor wants to keep the current steady so when the current changes it fights to slow the change by developing a voltage in opposition to the amount of change. If you want to fully understand electro-magnetics, study Maxwell's Equations which are the set of 4 equations that describe most of what you need to know.
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\$\begingroup\$ yes thanks buddy. i got your point and yes i read them 5 hours ago.. and i am satisfied now. thanks.. \$\endgroup\$ Commented May 7, 2016 at 1:56