| 摘要 |
PURPOSE:To secure a stable control characteristic all the time without entailing any excessive power consumption, by making a solenoid valve operate on such voltage as higher than the rated voltage at a suchlike operation range that rise time in the solenoid valve relatively comes long. CONSTITUTION:The ratio of T1 to T2 (the ratio of valve opening time to closing time) in a control signal to be added to a switch driving input terminal 9 grows large, and when a mean valve of the signal is larger than the setting voltage, no output is generated from a voltage comparator 11 and a relay switch 12 is thus opened. Therefore, a transistor switch Tr3 is in a state of being turned off, and rated power voltage by a first power source 7 is impressed on a solenoid valve's driving coil 1. Next, the valve opening time comes little as well as the ratio of T1 to T2 comes little, and when the output is generated out of the voltage comparator 11, the relay switch 12 is turned on whereby the transistor switch Tr3 is also turned on, cuasing a power circuit at the side of a second power source 6 to get operating, and such voltage as higher than the rated voltage is impressed on the driving coil 1 so that the soelnoid valve is opened in a good respective manner. |
