Cooktop

Gas cooktops consist of one or more gas burners with arrangements to control the rate of flow. They often have integral lighters or (in older models) pilot lights, and may have safety interlocks designed to reduce the risk of hazardous gas leaks. Gas cooking has been associated with negative health effects, such as reduced pulmonary function and a higher rate of respiratory symptoms in children. ==Electric==

Coil An electric coil cooktop uses electric elements that directly heat pots placed on them. They are inexpensive to buy and maintain, but are considered more difficult to clean than smooth-top models. Plate An electric plate cooktop is similar to a coil cooktop but uses plate-like base supports as opposed to coil supports. Ceramic radiation heating A ceramic radiation heating cooktop has a surface made of low-expansion thermal glass-ceramic that is transparent to infrared. 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 that 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, heat 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 that 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. If the induction coil is of lesser diameter than the cooking pot, and the pot has low thermal conductivity, use of high power can potentially warp the pot due to non-uniform heating. 6" coils are common in low-end portable units, which is smaller than most pots and pans. ==Ventilation and exhaust==

Cooktops often have a kitchen hood installed overhead to expel or filter smoke, fumes and undesirable odors that result from cooking. However, when installation of an updraft ventilation system is undesirable or impossible (for example in an open kitchen design), a cooktop with an integrated downdraft ventilation system can be used instead. Such systems draw cooking fumes downwards rather than upwards, eliminating the need of an overhead installation. They are, however, less effective than overhead systems, and may not be able to extract fumes emanating from taller pots. ==Placement==

Installed 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. Hot plate A hot plate or hotplate is a portable self-contained tabletop small appliance cooktop with one, two or more electric heating elements, or gas burners. A hot plate can be used as a standalone 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 or round surface. Hot plates can be used for traveling or in areas without electricity. ==References==