| 摘要 |
An electronic flow presetter having a plurality of functional circuits including a first set of circuits, composed of CMOS circuits, responsible for storing the operational state of the presetter, and a second set of circuits which are not required in connection with the storing of the operational state of the presetter, and a power pack associated with the presetter. The power pack includes a rectifier circuit 21 for normal energisation of both sets of functional circuits from an a.c. power supply, a storage capacitor 20 charged from the rectifier circuit 21 during normal use of the presetter, and switching means 23 to connect the first, but not the second, set of functional circuits, to the storage capacitor 20, on occasion of a drop in the voltage from the a.c. power below a reference level, to maintain storage of the operational state of the presetter immediately prior to the voltage drop. <IMAGE> |
