| 摘要 |
PURPOSE:To prevent destruction of memories at the time of disconnection of power supply, by fixedly connecting a battery and a battery switch and installing a change-over switch whose movable contact is normally connected to a discharging circuit side and, only when the switching operation is made, is connected to the voltage comparator for checking of the battery. CONSTITUTION:A battery 2 is normally connected to a battery switch 5 and set in a condition to constitute a discharging circuit. A check switch 8 is inserted into the discharging circuit and normally connects the battery to a movable contact or a charging resistance 4 and, only when the checking is performed, connects the battery to a voltage comparator 7. Even when disconnection of the power supply occurs at the time of changing over of the switch for checking, it is possible to supply power to a memory 1 through the battery switch 5 and, therefore, the data in the memory 1 is not destructed. |
