| 摘要 |
PURPOSE:To obtain the titled device for an air conditioner and the like from which a proper operation is expected, by a method wherein polluted air is detected by a smoke sensing resistance element and is purified by a heater. CONSTITUTION:A divided voltage at the junction of a resistor R1 and a smoke sensing resistor 1 is converted into a DC signal through a rectifying circuit mainly comprising an amplifier OP. When smoke is detected by a smoke sensing element A, the voltage across both terminals of a capacitor C increases with an increase in the resistance value of the smoke sensing resistor 1 and when the voltage becomes higher than a reference voltage Vref so that the output of a voltage comparator COP is turned to go to ''H'' level, a transistor Tr becomes conductive to supply an electric current to a honeycomb type resistance heater 8. As a result, the smoke component in the detected atmosphere coming into contact with the heater 8 is decomposed to produce a purified air current 7 which then flows out from a duct B. As the smoke sensing resistor 1, an MgCr2O4-TiO2 type metal oxide semiconductor is used. |
