| 摘要 |
The invention relates to a symmetrically wired device and a process for measurement of the concentration of ions, especially hydrogen (H+) ions, in a measurement liquid. The device comprises a pH-sensitive measurement electrode which is located in a measurement liquid, a reference electrode located in the measurement liquid, a comparison electrode which is located in the measurement liquid and which places the measurement liquid at a definable ground reference. Moreover, the device comprises means for forming a difference signal referenced to the ground reference from the difference between a measurement signal (phipH) of the measurement electrode and the reference signal (phiref) of the reference electrode. The difference signal is dependent on the ion concentration in the measurement liquid. To enable accurate and reliable measurement of the ion concentration in the measurement liquid with the symmetrically wired pH measurement device in spite of small power supply voltages of the electrical components of the device, especially at a power supply voltage less than 4 V, it is proposed that the device comprises compensation means for compensation of the noise potential (phichem) which arises between the comparison electrode and the measurement liquid FIG. 1.
|
