| 摘要 |
PURPOSE:To achieve a higher measuring accuracy of the density of an objective substance, by providing a reference electrode surrounding a majority part of a working electrode to upgrade a property of following a potential of a reference electrode with respect to a potential variation of an opposed electrode. CONSTITUTION:The output terminal of an operational amplifier 7 in which a DC power source 9 is connected to a positive input terminal to give a bias of -V to an earth potential 8 is connected to an opposed electrode 3 while a negative input terminal is connected to a reference electrode 3' to enable the controlling of a potential of the electrode 3' following a potential variation of the electrode 3. In this case, as the electrode 3' surrounds the entire circumference of a working electrode 2, it is under the quick effect of the potential variation caused by a current generated between the electrodes 2 and 3 to attain a better property of following the potential thereby achieving a higher measuring accuracy of the density of a substance as object. |
