A regular electric oven uses a large coiled resistor as a heating element. A large electric current is passed through this element which generates heat, similar to the tungsten filament of an incandescent light bulb.
An induction stove doesn't actually generate heat itself, but rather induces it the pot or pan. It does this using a rapidly oscillating magnetic field. This field induces an electric current in a ferromagnetic pan which generates heat, thus heating the food.
Induction stoves are faster, safer, and more energy efficient than traditional electric stoves. It requires significantly less electricity to create the magnetic field than it does to drive enough current through a resistor to make it heat up. They are safer because they don't actually generate heat themselves. After taking a pot off the "burner" (glass surface) it quickly begins to cool.
With regards to differences in the cooking process, there's not much. You just need to be aware that it heats up much more quickly and cools down much more quickly than a traditional electric stove. It does affect your choice of pans however. All aluminum pans will not work, nor will some lower quality stainless steel ones. If a magnet sticks to the pan then it will work just fine. The pan must also have a flat bottom to make full contact with the surface.
My name is Tom Wirt, with Clay Coyote Pottery. I'll try to shed some light on the intricacies of clay cooking pots, especially tagines.
You can use any flameware tagine directly on the glass stovetop. This includes, Emile Henry, Le Crueset, and Clay Coyote flameware. These are pots with either a metal base (Le Crueset) , or a type of ceramic called flameware (Emile Henry, Clay Coyote which is formulated and made to take direct heat.
Normal stoneware clay pots and earthenware pots will not do this. Stoneware should never go on a direct heating source, gas, electric or glasstop. It will crack with or without a diffuser.
Earthenware ceramic pots, typically identified by a reddish clay color and some absorbency by the bare clay (typically the bottom), do need a diffuser and should be started over a low heat. They can crack if used over sudden or too high a heat. Remember that these pots were originally used over charcoal fires.
Metal, obviously is fine.
The flameware ceramic pots, are designed for direct heat and are actually especially good on glasstops as the top spreads the heat better than electric or gas.
Clay is a insulator, not a conductor. Thus the heat doesn't spread much, but, with a highly liquid food like a tagine, the liquid spreads the heat. Basically a tagine is cooked at a simmer, even though the pot would take the heat.
Induction stoves require a metal plate with ceramic cookware to turn the electromagnetic force into heat.
You can find more info on my blog.
Best Answer
A small pan on an oversized burner wastes a lot of heat. Some more may be coupled into the pan but much will go into the room (so not wasted completely). It might damage the handle, especially with something low like a frying pan, as this heat is mainly radiated (the glass is meant to absorb very little). The inner burner may be so much weaker than the outer that even a fraction of the power of the outer is a significant increase compared to just the inner. I seem to recall using one with a 600W inner and 1200W outer - if even 1/4 of the power of the outer went into the pot it would be 50% more heat. The specs for yours don't go into quite enough detail but it looks like the inner might be 1200W and the outer 1800W, so not as marked as my example but it still makes a difference. As the heat is radiant, some heat will enter the sides of the pan, contributing to faster, if not very efficient, heating.
But when you say "cook quicker", how are you measuring cookedness? Is this a rate of reduction in volume (which would scale with power absorbed to a good approximation)? Or is it a subjective done-ness (which has more to do with time-at-temperature, so quite strongly affected by how quickly it reaches temperature). Coming to the boil quicker means you could use both until it boils then simmer using the inner ring only (assuming it's not finished when it first comes to the boil). This is likely to be more marked if you're starting from cold, as the additional power of the outer will cover some of the losses involved in warming up the surrounding parts of the stove.