| 摘要 |
A heating unit includes two tubular tungsten-halogen lamps (1, 2), each having a tungsten filament (3, 4). The lamps (1, 2) are supported within a ring (7) of ceramic fibre material and the unit is preferably mounted beneath an infra-red-transmissive cooktop to define a hotplate area (8) of a cooking hob. A control circuit provides a range of discrete power outputs of the lamps (1, 2), each power output corresponding to a power control setting set by a user of the cooking hob. The circuit includes a phase control circuit (19) for switching power to the lamps (1, 2) at a predetermined phase angle to achieve one or more of the lower power outputs. |
