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 ngerprints, deposits, scratches or enclosed air bubbles. The conductivity probe should be stored in a clean and dry environment.
The STCON3 utilizes the 4-ring potentiometric method for measuring conductivity, which incorporates a series of four stainless steel rings formed into the probe shaft. This design completely eliminates polarization, which occurs with the 2-plates amperometric method. Furthermore, without polarization the probe can measure a wider range of conductivity values
because it does not su er from electrolysis.
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 su cient time for the sensor to stabilize when measuring samples at di erent temperatures. A manual end-point is advised.
| Measurement Range | 3 µS/cm – 200 mS/cm; 1 – 100 °C |
| Working Environment | 10°C – 40°C, 85%RH, non-condensing |
| Working Environment | 50°F – 104°F, 85%RH, non-condensing |
| Net Weight | 85.0 g (3.0 oz) |
| Temperature Range | 0 °C – 100 °C |
| Measurement Range (Temperature) – | 0 °C – 100 °C |
| Dimensions (Length) | 135.0 mm (5.3 in) |
| Conductivity measuring range | 3 µS/cm – 200 mS/cm |
| Electrode Type | Conductivity |
| Shaft Material | Plastic |
| Cable (Length) | 1.1 m |
| Dimensions (ØDiameter) | 15.0 mm (0.59 in) |
| Temperature Sensor | 30 kΩ |
Note: For all International Orders, the buyer will be solely responsible for the customs clearance, duty, and taxes imposed on the package.