| 摘要 |
An apparatus for the rapid electrometric determination of ionic activities, especially the pH-value, p(Me)-value or p(L)-value of substances, by means of an ion sensitive or ion specific sensor of low or extremely high internal resistance. There is also provided a preferably transistorized amplifier circuit arrangement and an indicator device for the indication of the measurement values in analogue or digital form. According to the invention there is provided as the sensor an electrode measuring chain possessing measuring- and reference electrode means, such electrode-measuring chain exhibiting a clearly defined point of intersection of the isotherms, a constant electrical chain null point, an internal buffer of high buffer capacity and stable slope. A storage vessel is also provided for the measuring chain, and this storage vessel contains an activation solution to maintain said measuring chain under the influence thereof. Fixedly balanced resistor means for said amplifier circuit arrangement control the asymmetrical potential, the electrical null point of the apparatus, the temperature factor of the measuring chain and the amplification factor. |
