Cooktops are often found integrated with an oven, or may be standalone devices.
Cooktops are commonly powered by gas or electricity and sometimes oil or other fuels are used.
Gas cooktops consist of one or more gas burners with arrangements to control the rate of flow. They often have integral lighters or pilot lights and may have safety interlocks.
A ceramic hob consists of a low-expansion thermal glass-ceramic that is transparent to infrared, which houses radiant or halogen heaters below it. The advantage of this arrangement is that the heat can be quickly controlled.
Induction cooking involves the electrical heating of a cooking vessel by magnetic induction, instead of by radiation or thermal conduction from an electrical heating element, or from a flame. Because inductive heating directly heats the vessel, very rapid increases in temperature can be achieved, and changes in heat settings are fast, similar to gas.
In an induction cooktop ("induction hob" or "induction stove"), a coil of copper wire is placed under the cooking pot and an alternating electric current is passed through it. The resulting oscillating magnetic field induces a magnetic flux which repeatedly magnetises the pot, treating it like the lossy magnetic core of a transformer. This produces large eddy currents in the pot, which because of the resistance of the pot, heats it.
For nearly all models of induction cooktops, a cooking vessel must be made of, or contain, a ferromagnetic metal such as cast iron or some stainless steels. However, copper, glass, non magnetic stainless steels, and aluminum vessels can be used if placed on a ferromagnetic disk which functions as a conventional hotplate.
Induction cooking is quite efficient, which means it puts less waste heat into the kitchen, can be quickly turned off, and has safety advantages compared to gas stoves. Cooktops are also usually easy to clean, because the cooktop itself does not get very hot.
Cooktops are virtually ubiquitous in kitchens. They may be built into a stove along with an oven. Alternatively, cooktops are often installed independently in work surfaces.
A hot plate is a portable self-contained tabletop small appliance cooktop that features one, two or more electric heating elements or gas burners. A hot plate can be used as a stand-alone appliance, but is often used as a substitute for one of the burners from an oven range or a kitchen stove. Hot plates are often used for food preparation, generally in locations where a full kitchen stove would not be convenient or practical. A hot plate can have a flat surface, or round surface. Hot plates can be used for traveling or in areas without electricity.
- "Induction Cooking Technology Design and Assessment; M. Sweeney, J. Dols, B. Fortenbery, F. Sharp; Electric Power Research Institute (EPRI)" (PDF). Archived from the original (pdf) on 2015-09-10. Retrieved 2016-09-19. Paper presented at the 2014 ACEEE Summer Study on Energy Efficiency in Buildings