Inductor

What to observe

1. Start in Manual and shove the slider up hard. The electrons do not jump to speed, they accelerate, and while they are speeding up the coil takes almost the whole source voltage. A coil with no current in it acts like a break in the wire, which is the exact opposite of a capacitor.
2. Hold the slider still. The balls settle to a steady speed, the field stops growing, and the voltage across the coil falls to nothing. Once the current is constant a coil is just a piece of wire, and the resistor alone decides how fast the balls go.
3. Now drop the slider to zero. The electrons keep going, coasting on the field, and the coil now pushes instead of resisting to keep them moving. Watch the ladder: the coil voltage has flipped sign. It always opposes the change, never the current.
4. Turn the turns up, then slide the core from air to iron. Inductance climbs with N² and again with the core, and the same shove now produces a much slower ramp. That is inertia you can dial.
5. Switch to Battery and open the switch while current is flowing. There is nowhere for the electrons to go and they will not stop, so the coil produces hundreds of times the battery voltage and drives them across the gap as a spark. Tick the flyback diode and try again: the current gets a way home and the spike vanishes.
6. In AC, watch the current lag behind the voltage instead of leading it. The coil is always a quarter cycle late because voltage sets the rate of change, not the value. Raise the frequency and the current shrinks, since X_L = 2πfL: a coil passes DC and blocks high frequencies, which is the mirror image of the capacitor.
7. Compare the energy bars with the capacitor's. Here the energy lives in the field, ½LI², and it is paid back the moment you try to stop. In the capacitor it lives in the field between plates, ½CV², and is paid back the moment you let it. Same idea, different quantity held.