What is a conductivity meter?

A Conductivity meter (EC meter) measures the electrical conductivity in a solution

What is conductivity?

Conductivity is a physical feature of a material, and it is not part of a circuit as the current. It is a measure of a material’s ability to conduct an electric current.

What is the difference between the conductivity meter and TDS meter?

A TDS meter indicates the total dissolved solids (TDS) of a solution, while the Conductivity meter measures the ability of a substance to conduct electricity. Both terms are very related because, for example, the electrical conductivity of water is proportionally related to the concentration of ionized solids in it. The results of the TDS express the concentration of a substance, while the conductivity meter expresses their conductivity. TDS is expressed in parts per million (ppm) while the conductivity meters in mhos/cm.

The most accurate way to measure all TDS in water in a laboratory is to evaporate the water leaving behind dissolved solutes as residue, and then weighing the residue.

Conductometry

Though the use of conductometry to determine water purity began in 1776, Friedrich Kohlrausch (1840-1910 ) applied alternating current to water, acids and other solutions in 1860. The first instrument for volumetric analysis was invented by Robert Behrend (1856-1926) in 1883.

How does a conductivity meter work?

The basic model of conductivity meter employs four electrodes and a potentiometric method. The electrodes are usually made of platinum and they are arranged concentrically and the results are determined according to the distance between the electrode and their surface area. The electrodes are placed into de liquid to be measured and it applies a voltage. The meter converts this reading to milli- or micromhoss or Siemens*m2/m per centimetre. This value indicates the total dissolved solids.

Use of the Conductivity meter

The conductivity meter is very useful to calculate the concentration of the liquid. Conductivity meters are used heavily in agriculture to measure the salinity levels of surface water and of soil samples. This device is widely used in quality control due to the fact that it determines the number of dissolved ions in a water sample. Some models include both, conductivity test and TDS test. The use of this instrument applying temperature compensation allows readings that ensure the reliability and accuracy of measurement.

Types of conductivity meters

There is a wide variety of conductivity meters. Some of them include TDS measurements. There are portable conductivity meters that can be used inside and outside the laboratory facilities and the tabletop conductivity meters which are widely used in the laboratory. To see the different types, follow this link: Visit our catalog HERE

Conductivity controller: HERE

Portable Conductivity Meters: HERE

Benchtop conductivity meters: HERE