| 摘要 |
PURPOSE: To obtain an accurate display of remaining energy of a battery by supplying electric power from the battery to a pump and measuring the remaining energy of a power source and sounding the alarm when a measuring result is below a threshold. CONSTITUTION: A monitoring circuit 28 monitors voltage levels of contacts 42, 44 to a battery 40. When a charging voltage is detected, a signal showing that the main power source is an AC power source is sent to a microprocessing device 18. The monitoring circuit 28, also, compares a voltage of the contact 42 with that of the contact 44 and recognizes that a charging type battery is furnished when both of the voltages are identical. The microprocessing device 18 energizes and controls the whole circuit including a back light 24 in a normal actuation state. The microprocessing device 18 monitors the battery voltage determining a threshold from the information of a memory 21. When the voltage level detected by the monitor circuit 28 becomes below the threshold, a sound alarm 30 works.
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