Conductivity Probes STCON3 (2 µS/cm – 200 mS/cm)

Conductivity Probes

Basic Theory of Conductivity

Conductivity is measured in a wide range of industries and gives a readout of total ionic concentration within the sample. It is a rapid and inexpensive way of determining the ionic strength of a solution. A basic conductivity cell consists of a pair of electrodes that are placed in a sample. The ratio of the distance between the electrodes (D) and their surface area (A) is known as the cell constant K:   K= D/A [cm -1]

Each measuring cell has its own particular cell constant. It is recommended that you always determine the exact cell constant by using a calibration standard. In contrast to a pH electrode, the measuring cell does not change with time, at least if the sensor is used properly. The cell constant changes only if the surface of the probe changes, for example through fingerprints, deposits, scratches or enclosed air bubbles. The conductivity probe should be stored in a clean and dry enivronment.

The STCON3 conductivity probe has a built-in temperature sensor which is 30kΩ. When using STCON3, please consider the following:

1. Make sure the plastic shield is in place when measuring
2. Be sure the solution reached the line on the plastic shield and below the vent hole when measuring.
3. To prevent carry over from high to low conductivity solutions, rinse with distilled water between and after measurements.
4. Make sure the cell chamber is bubble-free.
5. Allow sufficient time for the sensor to stabilize when measuring samples at different temperatures. A manual end-point is advised.