| 摘要 |
<p>PURPOSE:To prevent the failure of the operation of a human body detecting sensor by infrared radiation by using an air velocity sensor of high sensitivity. CONSTITUTION:An air velocity sensor 14 of high sensitivity hot wire type is used which is capable of detecting the flow and fluctuation of air. The output end of the air velocity sensor 14 is connected to the input end of an amplifier 16. The output end of the amplifier 16 is connected to one input end of a comparator 18. Also the output end of a reference voltage generating circuit 20 for generating reference voltage is connected to the other input end of the comparator 18. Further the output end of the comparator 18 is connected via a switching circuit 22 to an illuminating device 24 which includes illumination of e.g. a fluorescent lamp. Therefore the illuminating device 24 is turned on when a human body detecting sensor 12 detects the presence of a person near it, while when the human body detecting sensor 12 detects the absence of any person near it the illuminating device 24 is turned off, thereby discriminating between the presence and absence of human bodies.</p> |
