What is a Conductivity Sensor?

From the water we drink to the oceans we cherish, from life-saving drug production to smart agricultural irrigation—our ability to safeguard and optimize these processes hinges on one essential measurement: Conductivity. Often unseen yet indispensable, the conductivity sensor operates as a silent guardian, providing critical data that keeps industries running and ecosystems protected.

1. The Introduction of Conductivity Sensor

A conductivity sensor is an instrument used to measure the conductivity of a solution. Its core function is to reflect the concentration or purity of the electrolyte by detecting the migration ability of ions in the solution. In actual construction, the conductivity sensor is mainly composed of electrode system, temperature compensation element and signal processing circuit.

2. Types and Working Principles of Conductivity Sensor

Two-electrode conductivity sensor

Two-electrode conductivity sensor is one of the common types, and its working principle is based on the current conduction between two electrodes. The conductivity of the solution affects the flow of electrical current as it passes through the solution. This type of sensor is simple in structure and low in cost, and is suitable for conductivity measurement of medium and low concentration solutions. Their main areas of application include water treatment, laboratory analysis, etc.

2 electrode conductivity sensor

Four-electrode conductivity sensor

The design of four-electrode conductivity sensor is more complicated than that of two-electrode conductivity sensor, but its accuracy and stability are higher. This type of sensor is used to apply current through two electrodes and the other two electrodes are used to measure voltage. The four-electrode sensor eliminates the impact of electrode pollution and can provide higher accuracy. It is appropriate for high-concentration solutions and complex environments, and is widely used in chemical, electric power, sewage treatment and other industries.

4 electrode conductivity sensor

Portable conductivity sensor

The portable conductivity sensor is a miniaturized device designed for field measurement and flow testing. Different from fixed sensors, portable conductivity sensors are often used in application scenarios such as water quality testing, environmental monitoring, and on-site analysis due to their lightness and ease of operation.

portable conductivity sensor

3. How to Install Conductivity Sensor

Disconnect the sensor power: Before wiring, you first need to ensure that the sensor is powered off. Using a suitable tool, cut the power cord of the sensor and label one end of the cable cord indicating the positive and negative poles of the power cord.
Choose the right terminal block: According to the actual application needs, choose the right number and type of terminal blocks. Ensure that the positive and negative terminals of each terminal block correspond to the positive and negative terminals on the cable wire. At the same time, use special crimping pliers to fix the cable wires to the terminal blocks.
Connect the power cord: Connect the power cord of the sensor to the terminal blocks. Note that the positive and negative poles of the power cord must be properly connected to ensure that the sensor is working properly.
Connect the signal wire: According to the actual application requirements, connect the signal wire of the conductivity sensor. One end of the signal line is connected to the terminal terminal, and the other end is connected to the input terminal of the external device. Ensure the signal wire that is connected correctly to make the electrical signal output from the sensor be read correctly.
Check wiring: After completing wiring, all wiring needs to be carefully checked to ensure that all connections have been properly fixed and there is no looseness or short circuit. At the same time, check whether the positive and negative poles of the power cord and signal cord are correctly connected.

4. How to Maintain Conductivity Sensors

Protect: Conductivity sensors are usually made of vulnerable materials, so violent collisions or squeezes should be avoided during use to avoid damaging the sensor.
Calibrate accuracy regularly: The accuracy of conductivity sensors will change over time, and regular calibration can ensure the accuracy of measurement results.
Clean and maintain: The sensor may be affected by pollutants during use, and the sensor should be cleaned in time to maintain its sensitivity and accuracy.
Store correctly: When the sensor is not in use, it should be stored in a dry environment with suitable temperature to avoid moisture or overheating.

5. Application of Conductivity Sensor

In the chemical fertilizers industry

Conductivity sensors ensure complete dissolution and precise proportioning by real-time monitoring of ion concentrations in raw material solutions. During key reactions such as neutralization and synthesis, they judge the reaction endpoint based on the changing trends of conductivity to avoid raw material waste or incomplete reactions. Meanwhile, they also assist in optimizing reaction conditions: By dynamically tracking changes in ion concentrations, they enable adjustments to temperature, pressure, or raw material feeding rates, thereby reducing the generation of by-products. This plays an indispensable role in raw material pretreatment, reaction monitoring, and other links, ensuring the efficiency of fertilizer production and the quality of products.

In the metallurgical industry

Conductivity sensors monitor the electrolytic refining process in real-time, optimizing electrolyte concentration and current efficiency, and continuously tracks wastewater ion levels, providing critical data for environmentally compliant discharge.

In environmental protection

Conductivity sensors play a role in monitoring water quality and the efficiency of wastewater treatment. For example, they can detect the presence of harmful substances in water, such as heavy metal ions and organic pollutants. During wastewater treatment, changes in conductivity can reflect how effective the treatment is, thereby guiding improvements to the process.

In the pharmaceutical industry

Conductivity sensors ensure production quality and safety through real-time monitoring: They maintain water quality compliance in purified water and water for injection systems, while warning of contamination risks. In API synthesis, they track ion changes to precisely control reactions and reduce impurities. In cleaning validation, they confirm the absence of residues in equipment using low and stable rinse water conductivity readings, preventing cross-contamination. In formulation testing, they verify the uniformity of electrolytes and screen for container seal integrity. Ultimately, they support regulatory compliance with real-time data, facilitating the production of safe and effective pharmaceuticals.

In the biochemical industry

Conductivity sensors are used to monitor critical processes. During chromatographic separation, they enable the purification of biological molecules such as proteins and nucleic acids by precisely controlling the conductivity gradient of the eluent. In cell culture, changes in the conductivity of the medium reflect nutrient consumption and metabolic status, thereby optimizing cell growth and fermentation efficiency.

In the power industry

Conductivity sensors are applied to assess the quality and performance of transformer oil. The conductivity of transformer oil can indicate the levels of moisture and impurities present, helping determine if the oil needs replacement or treatment. Additionally, they monitor the conductivity of coolants in power equipment to ensure the cooling system operates normally.

conductivity sensor six parts

6. Future Development

With the continuous progress of science and technology, conductivity sensors will also usher in a broader development prospect. First of all, the accuracy of the sensor will continue to improve, allowing more accurate measurements. Secondly, the size and cost of the sensor will be further reduced to meet the needs of more scenarios. In addition, with the rapid development of intelligent technology, conductivity sensors will also be connected with other intelligent devices to realize data intercommunication and sharing, providing users with a more convenient experience.