| 摘要 |
PURPOSE:To improve the responsiveness of a humidity control circuit by forming an oscillating circuit by the use of an element of which electrostatic capacity changes with relative humidity, and comparing the voltage charged by the pulses of the oscillating circuit and a set voltage to control humidification. CONSTITUTION:A humidity detecting element 10 is so constituted that its electrostatic capacity increases with an increase in relative humidity and that said capacity changes roughly linearly in a practicable use range. A serial circuit of resistors (R) 5, 6 is connected via a switch 2 to an electric power source 1, and the connecting point (c) of the R5, 6 is connected to the positive input terminal of a differential amplifier 9. The output point (f) of the amplifier 9 is connected via R11 to the point (c) and via R12 to the negative input terminal, and the element 10 is connected to the point (e) and to the other terminals of the R6, to form an oscillating circuit. The oscillating output drawn out through R13, and charges a capacitor 17. The charged voltage thereof is applied to a differential amplifier 19 and is compared with the voltage set by R7, 8. The output of the amplifier 19 is connected via a transistor 4 to a relay 3 to drive a humidifier. Therefore the comfortable humidification is accomplished with good responsiveness. |
