How they operate
An induction cooker uses induction heating for cooking. Unlike other forms of cooking, heat is generated directly in the pot or pan (cooking vessel), as opposed to being generated in the stovetop by electrical coils or burning gas. To be used on an induction cooker, a cooking vessel must be made of a ferromagnetic metal. In an induction cooker, a coil of copper wire is placed underneath the cooking pot made of a material which must be electrically conductive and ferromagnetic.

An alternating electric current flows through the coil, which produces an oscillating magnetic field. This field induces an electric current in the pot. Current flowing in the metal pot produces resistive heatingwhich heats the food. While the current is large, it is produced by a low voltage.

Induced current can heat any type of metal, but the magnetic properties of a steel vessel concentrate the current in a thin layer near the surface, which makes the heating effect stronger. Practical induction cookers are designed for ferromagnetic pots; users are advised to use only pots on which a magnet will stick. Non-ferrous metals have askin depth that is too thick, lowering the resistance seen by the induced current and so making such metals unusable on an induction hob. Since heat is being generated by an induced electric current, the unit can detect whether cookware is present (or whether its contents have boiled dry) by monitoring how much power is being absorbed. That allows such functions as keeping a pot at minimal boil or automatically turning an element off when the pot runs out water or the cookware is removed from it. This form of cooking has certain advantages over conventional gas flame and electric cookers, as it provides rapid heating, improved thermal efficiency, and greater heat consistency, greater safety yet with precise control similar to gas. In situations in which a hotplate would typically be dangerous or illegal, an induction plate is ideal, as it creates no heat itself. The time to boil a certain amount of water depends upon the amount of water but it is typically a few minutes. Heating is much faster without water, e.g., for stir-frying, a thin pan containing three tablespoons of oil may heat up to stir-fry temperature in as little as ten seconds. Induction cookers are safer to use than conventional cookers because there are no open flames and the element itself reaches only the temperature of the cooking vessel; only the pan generates heat. Induction cookers are easy to clean because the cooking surface is flat and smooth, even though it may have several heating zones.
The cooking surface is made of a material which is a poor heat conductor, so only minimal heat is transferred from the pot to the cooking surface. In normal operation the cooking surface stays cool enough to touch without injury after the cooking vessel is removed. Since the cooking surface is not directly heated, spilled food can not burn on the surface.

Efficiency
Induction cook top technology gives a far more efficient transfer of energy than a gas flame or heated electrical element and so boiling a pan of water, for example, is much quicker. If you are using electricity, induction cooking is the hands down winner in terms of cost.

Limitations
Cookware must be compatible with induction heating; glass and ceramics are unusable, as are solid copper or solid aluminum cookware. Manufacturers advise consumers that the glass ceramic top can be damaged by impact. Aluminum foil can melt onto the top and cause permanent damage or cracking of the top.

The market for induction stoves is dominated by German manufacturers, such as Bosch, Miele and Siemens. Taiwanese and Japanese electronics companies are the dominant players in induction cooking for East Asia