| 摘要 |
PURPOSE:To eliminate occurrence of malfunction by providing a power source for a latching solenoid valve independently of the power source for other control devices. CONSTITUTION:A temperature setting and voltage comparison circuit 53 is constituted, and supposing that the output voltage of a volume 57 which can be arbitrarily set is VVR, the impedance of the circuit 53 is converted by an operation amplifier 59, and a negative input voltage V4 of a voltage comparator 66 becomes about (R63.VVR)/(R60+R63). When a temperature sensor 62 is heated, its resistance value drops and a positive input voltage V2 becomes lower than the negative input voltage V4, the output of the comparison circuit 53 changes from VH to VL. Accordingly, the output of a conversion circuit 67 changes from VL to VH, and in the OFF coil 100b of a valve 100 an electric current flows because of the voltage build-up from a dry battery 113 which is a second power source by means of an OFF pulse generating circuit 103, and the valve 100 is closed to extinguish a main burner 112. There is, therefore, no change in the electromotive force of a dry battery 1 even if the latching solenoid valve is turned ON or OFF. |
