| 摘要 |
<p>A temperature sensor (13) senses the temperature of a heated area (15) eg of a cooking vessel and a switching device 22 switches between different combinations of heating elements 26-29 to provide power outputs, in dependence on the difference between the sensed temperature and a selected power output set by a user-operable control 17. The heating apparatus includes a generally circular tray (1) containing a layer (2) of thermally-insulative material and supporting four infra-red-emitting, tungsten-halogen lamps (5), each having a tungsten filament (7). The apparatus is mounted beneath a layer (11) of glass ceramic to form a cooking hob. On/off switching of the lamps (5) provides temperature control and energisation and de-energisation of each of the lamps (5) may be implemented in a sequential manner. <IMAGE></p> |
