Conductivity Sensor / Resistivity Sensor - Overview - METTLER TOLEDO

    Conductivity Sensor / Resistivity Sensor

    Accurate and reliable conductivity / resistivity sensors for process and pure water applications


    Conductivity Frequently Asked Questions

    What does a conductivity sensor measure?

    Conductivity sensors measure the ability of a solution to conduct an electrical current. It is the presence of ions in a solution that allow the solution to be conductive: the greater the concentration of ions, the greater the conductivity.


    How do you calibrate a conductivity sensor?

    A conductivity sensor can be calibrated against a solution of known conductivity (much like calibrating a pH sensor against a solution of a known pH). Alternatively, you can use a device that contains a range of very precise resistors that duplicate known conductivity measurements.


    How many types of conductivity sensor are there?

    There are two types of conductivity sensor: contacting and inductive. With contacting sensors the electrodes that measure the conductivity are in direct contact with the solution. An alternating voltage is applied to the electrodes. This causes the ions in the solution to move back and forth between the electrodes, creating a current which is measured and converted to a conductivity measurement. This type of sensor is very good for measuring low conductivity solutions where there are very few solid particles that could collect around the electrodes and interfere with the measurement, e.g., pure water. For high conductivity solutions or if the solution would corrode electrodes or contains a large amount of solid particles, inductive sensors are required. These sensors use two coils of wire encased in a plastic body. Current flowing through one coil induces a current to flow through the other. The amount of induced current is dependent on the conductivity of the solution.


    What unit is conductivity measured in?

    Conductivity is measured in siemens per cm (S/cm). A conductivity of 1 S/cm is actually quite high, so most conductivity measurements involve solutions where conductivity is measured in mS/cm (thousandths of a S/cm) or in μS/cm (millionths of a S/cm). Drinking water is generally between 50 and 1500 μS/cm.

    InPro 7100 4-electrode conductivity sensor
    Inductive Conductivity Sensors
    Conductivity / Resistivity Sensors

    2-/4-Electrode Conductivity Sensors

    Inductive Conductivity Sensors

    Conductivity / Resistivity Sensors

    2-electrode sensors specially for low conductivity and 4-electrode sensors for medium to high conductivity.
    Easy-to-use sensors for measuring under the harshest conditions.
    Thornton offers a wide variety of conductivity / resistivity sensors to accommodate pure water applications.
    Wide range of applications
    from biopharmaceutical to chemical processes
    Highest accuracy
    at very low to medium conductivities
    Compliance through certification package
    Lowest maintenance
    due to robust design
    Long lifetime through
    excellent chemical resistance
    Reliability thanks to
    individual testing of cell constant to ensure highest possible measuring accuracy
    Highest accuracy available
    for pure water measurement
    Sensor diagnostics and Plug and Measure for models
    with Intelligent Sensor Management (ISM)
    Wide choice of fittings and certified materials
    to meet process requirements
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