| 摘要 |
PURPOSE:To detect the residual capacity of a battery with a slight discharge rate at a desired time while scarcely affecting the residual quantity of electricity by determining the arrival of a fixed terminal voltage, the time covered until the arrival thereof and the like with a short time discharge of a large current. CONSTITUTION:A short time timer 7 and a time counter 10 are actuated through a manual button 2 or a long time timer 6 and the like. The current discharged of a secondary battery to be measured increases in linearity with capacitors 4 and 70 similar in the property and a heavy discharge switching element 3 and the like through a constant current driver 5, which causes the discharge of a large current negligible in a short time. Consequently, the terminal voltage of a battery 1 lowers and the arrival of the reference voltage with a comparator 8 is detected to reset the timers 6 and 7. The count of the counter 10 based on the time covered until the arrival thereof corresponds to a computed value of the quantity of residual electricity in terms of ampere-hour. This enables the detection of the residual capacity of a secondary battery with a slight discharge rate at a desired time little affecting the quantity of residual electricity utilizing the characteristic of increase in the internal resistance with a decrease in the quantity of electricity storage. |
