| 摘要 |
PURPOSE:To measure the concentration of alcohol in a stable manner by a method wherein a pair of electrodes are immersed in an alcohol-mixed liquid, charge and discharge are repeated and charge and discharge currents corresponding to changes in an electrostatic capacity on the occasion are converted into pulse signals and outputted. CONSTITUTION:A pair of electrodes 1 and 2 are immersed in an alcohol-mixed fuel in a fueled tank for a internal combustion engine, or the like. An oscillation circuit composed of NAND circuits 3 and 5 and resistors R1 to R4 conducts charge and discharge repeatedly through the paired electrodes 1 and 2, while converting currents of the aforesaid charge and discharge corresponding to changes in an electrostatic capacity between the electrodes 1 and 2 into square pulse signals of a prescribed frequency and outputting the same. Since the frequency of these output pulse signals and the concentration of alcohol have a prescribed relationship between them, the concentration of the alcohol in the aforesaid alcohol-mixed fuel can be measured in a stable manner by measuring the frequency of the output pulse signals. |
