The process liquid to be measured may have an ohmic resistance outside the analyzer's measuring range. For this reason, there are sensors with different geometry available. These differences are expressed in the Cell Constant (CC). The CC of a sensor is the ratio of distance and the surface area of two measuring plates (see Figure 1).
Although the exact cell constant is specific for an individual sensor, they are grouped by nominal value: cell constants of 0.01, 0.02, 0.1, 1, and 10 cm -1 are usual. Measuring only specific conductivity, e.g., Siemens or µS, this does not provide any information on the purity of the liquid. For this, it is necessary to multiply by the cell constant (CC). This is the key point of conductivity measurement. The conductivity must be expressed per unit distance e.g., Siemens per cm (S/cm).
Figure 1. Cell Constant (CC) calculation
For more information check out our Technical Information: Contacting Conductivity sensor selection guide.
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