| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To solve the problem wherein a thermal sensor utilizing the radiation phenomenon of a heater is general as wind speed and air volume sensors conventionally, a platinum sensor whose part costs are high is used for a sensor for detecting wind speed and a sensor for compensating a temperature for this type of sensor, and sensors having aligned resistance temperature characteristics must be used for increasing costs greatly. <P>SOLUTION: An inexpensive diode is used as a heat sensitive element for detecting wind speed, and a heat sensitive element for compensating temperature. A forward voltage when a constant current is allowed to flow to the diode is approximately -2.0 mV/°C, namely shows improved linearity, so that the diode is utilized also as a temperature sensor. However, the forward voltage changes according to the level of temperature and current in the diode, which differs from a platinum resistor and a thermistor, so that a constant power circuit that becomes fully practical by a simple circuit is used although the diode needs to be driven with constant power for use as a thermal element. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
