| 摘要 |
PROBLEM TO BE SOLVED: To obtain a device capable of easily measuring the remaining life of a cell. SOLUTION: A light bulb 07 is serially connected to a serially combined circuit of dry cells to be measured EA03 and EB05 to receive the emission of the light bulb 07 by a photodetector CdS 11. The potential of the voltage of a 1.5-V power source 25 is divided by a potential divider constituted of a serial circuit of the CdS 11 and a variable resistance 15 and a resistor R4 and is inputted to the gate of an FET 21. When the emission intensity of the light bulb 07 is sufficient and the resistance value of the CdS 11 is less than the value of a resistor R3, the FET 21 is ON, an LED 19 is lighted, an FET 29 is OFF, a relay 31 is not in an operative state, and a clock 33 is in an operative state. When the dry cells EA03 and EB05 are consumed and the emission intensity of the light bulb 07 starts to be lowered to the contrary, the resistance value of the CdS 11 is rapidly increased. When it exceeds the value of the resistor R3, the input voltage of the FET 21 becomes less than an input threshold, the FET 21 is OFF, the LED 19 is turned off, the FET is ON, the relay 31 is operative, the clock 33 is halted. Then it is possible to measure a remaining time.
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