To maintain a set temperature, the element is cycled on and off, usually by a switch called an infinite switch, so named because it theoretically provides an infinite number of heat settings. They heat by radiation, much like a sunlamp heats your skin. These units do not heat the pot or pan by direct contact (conduction) like coil surface units.
These have a radiant element (something like a very intense sunlamp) underneath a glass surface. Since the surface unit coil is flat, flat-bottomed cookware provides the best contact with these units and thus the most efficient operation.Ī fairly recent development is the radiant heat cooktop. Heating occurs mainly by conduction that is, the direct contact of the heating element to the cookware. On higher settings, the element glows red when operating. Usually these are nichrome wire, surrounded in ceramic insulation, with a steel sheath around the ceramic. In most cooktops, the heating element is simply a big resistor wire, with enough resistance to generate a high heat. Also, in some fixed-temperature switch applications, 110 volts is applied to a 220 volt surface unit (burner) to achieve a 'low' heat setting. Some smaller 'apartment' cooktops run on 110 volts. The heating elements usually run on 220 volts, and accessories such as lights, timers and rotisserie motors run on 110 volts. Most electric cooking equipment uses two different electrical circuits.
