| 摘要 |
PURPOSE:To prevent important dangers such as damage from being caused by the abnormal operation of controlled elements, by performing surely an initial reset at a power source restoration time after the breaking of a commercial power source dependent upon instantaneous power failure. CONSTITUTION:When commercial power source 1 is broken, transistor 11 is opened, and output voltage A of DC power source 4 starts lowering gradually. Meanwhile, capacitor 16 is not discharged, and the voltage value rises, and consequently, transistor 20 is closed. As a result, the charge charged in capacitor 5 with a polarity shown in the figure is discharged. Next, when power source 1 is restored, the charge of capacitor 16 is discharged through transistor 11, and transistor 20 is opened. Consequently, a high voltage approximately equal to the output voltage of DC power source 4 is applied to the initial reset terminal of micro computer 7 at a restoration time of power source 1, thus making it possible to reset to program counter to the initial state. |
