Electronic – Working principle of inductors

analoginductorvoltage

Assume we have this circuit:

schematic

simulate this circuit – Schematic created using CircuitLab

At t=0s we decide to close the switch, then current will start flowing through the circuit and around the inductor a magnetic field will be induced.

My questions:
According to Faraday's law, the electric voltage generated on a coil will depend on the change of the magnetic flux through the coil. Since the magnetic field grows at a constant rate shouldn't the back emf of the inductor remain the same? Why does it have the form it does?

Best Answer

Once the switch is closed the voltage across the inductor is constant and equal to the voltage of the source. Based on the schematic you have drawn, and assuming ideal elements, there is no other possibility.

The rate of change of the current through the inductor, \$\frac{di}{dt}\$ will therefore also be constant.

So, the current will increase linearly.

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