Understanding the Working Principle of a Conductivity Meter

Understanding the working principle of a conductivity meter is essential for those who work in fields such as chemistry, biology, environmental science, and various industries where the measurement of the conductivity of a solution is crucial. A conductivity meter, also known as a conductometer, is a device that measures the ability of a solution to conduct an electric current. This article aims to elucidate the working principle of a conductivity meter in a comprehensive manner.

The fundamental principle behind a conductivity meter is Ohm’s law, which states that the current passing through a conductor between two points is directly proportional to the voltage across the two points. In the context of a conductivity meter, the conductor is the solution whose conductivity is being measured. The meter applies a voltage across two electrodes immersed in the solution, and the resulting current is measured. The conductivity of the solution is then calculated based on the measured current and the applied voltage.


The conductivity meter consists of four main components: the electrodes, the oscillator, the converter, and the display. The electrodes, usually made of platinum or Stainless Steel, are immersed in the solution and are responsible for applying the voltage and measuring the current. The oscillator generates an alternating current (AC) voltage, which is applied across the electrodes. The use of AC voltage prevents polarization of the electrodes, which could otherwise distort the measurements.

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The current that flows between the electrodes is proportional to the conductivity of the solution. This current is converted into a voltage signal by the converter, which is then processed and displayed as a conductivity value on the display. The display can be digital or analog, depending on the design of the meter.

It’s important to note that the conductivity of a solution is influenced by several factors, including the concentration and type of ions in the solution, the temperature of the solution, and the distance between the electrodes. Therefore, to ensure accurate measurements, these factors must be controlled or accounted for. Most modern conductivity meters have temperature compensation features that adjust the conductivity reading based on the temperature of the solution. Additionally, the distance between the electrodes is fixed in the design of the meter to eliminate this as a variable.

ROS-8600 RO Program Control HMI Platform
Model ROS-8600 Single Stage ROS-8600 Double Stage
Measuring range Source water0~2000uS/cm Source water0~2000uS/cm
\\u3000 First level effluent 0~200uS/cm First level effluent 0~200uS/cm
\\u3000 secondary effluent 0~20uS/cm secondary effluent 0~20uS/cm
Pressure sensor(optional) Membrane pre/post pressure Primary/ secondary membrane front/rear pressure
pH Sensor(optional) —- 0~14.00pH
Signal collection 1.Raw water low pressure 1.Raw water low pressure
\\u3000 2.Primary booster pump inlet low pressure 2.Primary booster pump inlet low pressure
\\u3000 3.Primary booster pump outlet high pressure 3.Primary booster pump outlet high pressure
\\u3000 4.High liquid level of Level 1 tank 4.High liquid level of Level 1 tank
\\u3000 5.Low liquid level of Level 1 tank 5.Low liquid level of Level 1 tank
\\u3000 6.Preprocessing signal\\u00a0 6.2nd booster pump outlet high pressure
\\u3000 7.Input standby ports x2 7.High liquid level of Level 2 tank
\\u3000 \\u3000 8.Low liquid level of Level 2 tank
\\u3000 \\u3000 9.Preprocessing signal
\\u3000 \\u3000 10.Input standby ports x2
Output control 1.Water inlet valve 1.Water inlet valve
\\u3000 2.Source water pump 2.Source water pump
\\u3000 3.Primary booster pump 3.Primary booster pump
\\u3000 4.Primary flush valve 4.Primary flush valve
\\u3000 5.Primary dosing pump 5.Primary dosing pump
\\u3000 6.Primary water over standard discharge valve 6.Primary water over standard discharge valve
\\u3000 7.Alarm output node 7.Secondary booster pump
\\u3000 8.Manual standby pump 8.Secondary flush valve
\\u3000 9.Secondary dosing pump 9.Secondary dosing pump
\\u3000 Output standby port x2 10.Secondary water over standard discharge valve
\\u3000 \\u3000 11.Alarm output node
\\u3000 \\u3000 12.Manual standby pump
\\u3000 \\u3000 Output standby port x2
The main function 1.Correction of electrode constant 1.Correction of electrode constant
\\u3000 2.Overrun alarm setting 2.Overrun alarm setting
\\u3000 3.All working mode time can be set 3.All working mode time can be set
\\u3000 4.High and low pressure flushing mode setting 4.High and low pressure flushing mode setting
\\u3000 5.The low pressure pump is opened when preprocessing 5.The low pressure pump is opened when preprocessing
\\u3000 6.Manual/automatic can be chosen when boot up 6.Manual/automatic can be chosen when boot up
\\u3000 7.Manual debugging mode 7.Manual debugging mode
\\u3000 8.Alarm if communication interruption 8.Alarm if communication interruption
\\u3000 9. Urging payment settings 9. Urging payment settings
\\u3000 10. Company name,website can be customized 10. Company name,website can be customized
Power supply DC24V\\u00b110% DC24V\\u00b110%
Expansion interface 1.Reserved relay output 1.Reserved relay output
\\u3000 2.RS485 communication 2.RS485 communication
\\u3000 3.Reserved IO port, analog module 3.Reserved IO port, analog module
\\u3000 4.Mobile/computer/touch screen synchronous display\\u00a0 4.Mobile/computer/touch screen synchronous display\\u00a0
Relative humidity \\u226685% \\u226485%
Environment temperature 0~50\\u2103 0~50\\u2103
Touch screen size 163x226x80mm (H x W x D) 163x226x80mm (H x W x D)
Hole Size 7 inch:215*152mm(wide*high) 215*152mm(wide*high)
Controller size 180*99(long*wide) 180*99(long*wide)
Transmitter size 92*125(long*wide) 92*125(long*wide)
Installation method Touch screen:panel embedded; Controller: plane fixed Touch screen:panel embedded; Controller: plane fixed

In terms of calibration, conductivity meters are typically calibrated using solutions with known conductivity values. This ensures that the meter is providing accurate readings. Regular calibration is essential for maintaining the accuracy and reliability of the meter.

In conclusion, a conductivity meter operates on the principle of Ohm’s law, applying a voltage across two electrodes immersed in a solution and measuring the resulting current to calculate the conductivity of the solution. The meter consists of four main components: the electrodes, the oscillator, the converter, and the display. The conductivity of a solution is influenced by several factors, including the concentration and type of ions in the solution, the temperature of the solution, and the distance between the electrodes. Therefore, these factors must be controlled or accounted for to ensure accurate measurements. Regular calibration using solutions with known conductivity values is also essential for maintaining the accuracy and reliability of the meter.