# Can Inductor force abrupt current change through another inductor?

Say the 3H branch of the circuit was connected to the 1V source for a long time such that 500mA current is flowing through the 3H inductor.

Then after long time the switch was connected to 1H inductor branch

Now, the currents can't change abruptly in an inductors. Therefore 500 mA can't flow through 1H branch just after switch transition, neither the current can drop to zero because 3H inductor will prevent it from happening.

My question is what will be the current in the circuit just after switch transitioning happen?

• The ideal circuit is not physical. In reality you will get some sparks. Jan 19, 2018 at 17:53
• It's just the same as connecting one charged capacitor to another one... try to think about this... Jan 19, 2018 at 17:54
• @carloc I think you won't get sparks with caps :) Jan 19, 2018 at 17:56
• The current cannot change abruptly in the inductor, correct. But if your switching a charged inductor, it creates a large voltage across the inductor. Jan 19, 2018 at 17:57
• @EugeneSh. Well it may spark or not but that's not the point. The analogy is that when you connect the two capacitors together a sharp current spike will equalize voltages.Here, dually, a sharp voltage spike will equalize currents. Then a lot could be said about what "spike" actually means with different degrees of ideality considered, but this applies equally to both cases :) Jan 19, 2018 at 19:09