| 摘要 |
PURPOSE:To enhance measuring accuracy by changing stepping voltage according to the magnitude of the change quantity of an electrolytic current and reducing said stepping voltage in a part where the change quantity of the electrolytic current is large. CONSTITUTION:Predetermined voltage is stepwise applied between the acting electrode 40 and opposed electrode 42 of a measuring cell 51. A current/voltage converter 44 converts the electrolytic voltage of the measuring cell 51 to voltage and an A/D converter 46 converts the electrolytic current converted to voltage to a digital current. CPU 49 controls the sampling point of time of the digitized electrolytic current and the sampled electrolytic current is stored in a memory. CPU 49 subtracts the electrolytic current signal of the previous stage from said electrolytic current signal and calculates the change quantity of the electrolytic current due to stepping voltage. Next, this change quantity is compared with a threshold value and, on the basis of the magnitude relation between both of them, the stepping voltage to be applied to the next stage is set. |
