| 摘要 |
Heating apparatus includes four tungsten-halogen lamps (5) mounted beneath a layer (11) of glass ceramic, which forms the top surface of a cooking hob. An electronic temperature sensing device (12), which is preferably a thermistor or thermocouple, is arranged so as to be in contact with, or closely adjacent to, the undersurface of the layer (11), so that the device (12) produces a signal (13) indicative of the operating temperature of the undersurface of the layer (11). The signal (13) is compared with a reference signal indicative of the maximum operating temperature of the glass ceramic and the lamps (5) are de-energised when the signal (13) exceeds the reference signal. |
