how conductivity is measured

Conductivity is the measure of a material's ability to conduct an electric current. It is an essential factor in countless industries such as electronics, manufacturing, and water treatment. The measurement of conductivity is crucial because it indicates the degree of ionization of a solution, which in turn is a gauge of the concentration of dissolved salts and other chemical substances.

The measurement of conductivity cannot be performed using conventional electronic measurement methods. Several tools and instruments are used to measure electrical conductivity of liquids and solutions, which vary depending upon the application and the specific requirements of the industry. In this article, we will discuss how conductivity is measured and the techniques involved.

Conductivity Measurement Methods

Conductivity is measured using a variety of tools and techniques, with most methods relying on the use of electrodes. Electrodes are placed in a liquid or solution, a voltage is applied, and the resultant current is measured. Different types of electrodes and conductivity measurement devices are available depending on the industry, the liquid or solution being measured, and the required accuracy.

Types of Electrodes

Electrodes come in various forms, each offering particular benefits and advantages over others, depending on their application. Below are different types of electrodes frequently used in measuring conductivity.

1. Platinum electrodes

Platinum electrodes are incredibly stable and resistant to corrosion, making them excellent conductors, especially in harsh environments.

2. Glass electrodes

Glass electrodes consist of a glass body that is filled with a solution that contains both charged and uncharged ions. They are often used to measure conductivity in solutions that include anions and cations.

3. Metal electrodes

Metal electrodes are typically made of copper, nickel, or steel. They are frequently used in industrial applications where higher conductivity ranges are encountered.

4. Carbon electrodes

Carbon electrodes are used mostly in low-conductivity solutions, and they work exceptionally well in corrosive environments.

5. Pencil electrodes

Pencil electrodes are made from graphite and are used to measure the conductivity of molten semiconductors and high-temperature solutions.

Measuring Conductivity

Measuring conductivity involves passing an alternating current of a specific frequency through a liquid or solution between two electrodes placed in the solution. The voltage drop between the electrodes created by this current is then measured, providing a value of the solution's conductivity.

Instruments are used for measuring conductivity, including handheld conductivity meters, benchtop conductivity meters, and online conductivity meters.

1. Handheld Conductivity Meters

Handheld meters are portable and ideal for in-field conductivity measurement. They typically come with probes, which can be made of different materials, such as platinum, glass, or metal, depending on the sample's nature.

2. Benchtop Conductivity Meters

Benchtop conductivity meters are more advanced than handheld meters and offer a higher degree of accuracy in conductivity measurements. They are often used in research laboratories and other specialized applications where a high degree of precision is essential.

3. Online Conductivity Meters

Online conductivity meters are used in industrial applications to monitor conductivity levels continuously. They are installed directly in pipes, tanks or process vessels, providing real-time data, which can be used to adjust and control processes automatically.

Conclusion

Conductivity is one of the essential measurements, particularly in industries dealing with liquid products or solutions. Accurate measurement of conductivity requires the right tools and electrodes for specific applications. Whether for quality control or process automation, understanding conductivity and its measurement is essential for any industry where electrical current passes through a solution. The application of the correct tools and techniques can help ensure that products are safe and meet required standards.