| 摘要 |
PURPOSE:To prevent the polarization phenomenon of the dew condensation sensor, by connecting the dew condensation sensor to a resistor circuit by which an oscillating period of an oscillator is determined and to which AC voltage is applied at the time of the oscillation. CONSTITUTION:The oscillator 10 has an inverter 1. Said inverter 1 has a capacitor circuit 8 including discharge capacitor 2 and a resistor circuit 9 comprising a series circuit of a resistor 3 and the dew condensation sensor 4. Thus a CR oscillator is constituted. When the inverter 1 is connected to a power source, the capacitor 2 is charged through the resistor circuit 9 comprising the resistors 3 and 4. When it is charged to a specified potential, it is inverted and the discharge current flows through the resistor circuit 9. Said charging and discharging are repeated and said oscillating output is obtained through a resistor 6. The period of th charging and discharging depends on the capacity of the capacitor 2 and the resistance of the resistor circuit 9. The period becomes short when the humidity at the dew condensation sensor 4 becomes high, and the period becomes long when the humidity becomes low. |
