Conductivity of Water

Electrical conductivity is an indicator of water quality. Conductivity data can determine concentration of solutions, detect contaminants and determine the purity of water. YSI conductivity sensors measure conductivity by AC voltage applied to nickel electrodes. These electrodes are placed in a water sample (or other liquid), where the current flows through the electrodes and the sample. Current level has a direct relationship with the conductivity of the solution.

Conductivity is the ability of a material to conduct electrical current. The principle by which instruments measure conductivity is simple - plates/wires are placed in the sample, a potential is applied across them (normally a sine wave voltage), and the current is measured. Conductivity, the inverse of resistivity is determined from the voltage and current values according to Ohm's law.

Since the charge on ions in solution facilitates the conductance of electrical current, the conductivity of a solution is proportional to its ion concentration. In some situations, however, conductivity may not correlate directly to concentration. Ionic concentrations can alter the linear relationship between conductivity and concentration in some highly concentrated solutions.

The basic unit of conductivity is the siemens (S), sometimes referred to as mho. Since cell geometry affects conductivity values, standardized measurements are expressed in specific conductivity units (S/cm) to compensate for variations in electrode dimensions.

Conductivity measurements, along with temperature, also allow for salinity values to be calculated through algorithms.

Conductivity meters can use different types of sensors such as the non-wiped conductivity field sensor shown below.

Conductivity of Water | Conductivity Meters | Specific Conductance

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Featured Conductivity Products

EcoSense EC300A Conductivity Meter

Conductivity, TDS, Salinity, Temperature. Instrument Only


MultiLab 4010-1W

Single channel benchtop multiparameter instrument


Pro30 Conductivity Meter

Portable Conductivity, Salinity, TDS, and Temperature Sampling Handheld Meter


ProQuatro Multiparameter Meter

Portable Sampling Handheld Meter for DO, Conductivity, Salinity, TDS, pH, ORP, Ammonium, Nitrate, Chloride, Temperature and more


EcoSense EC30A Conductivity Pen

Easy-to-use conductivity, TDS and temperature instrument


Pro2030 Dissolved Oxygen and Conductivity Meter

Portable Dissolved Oxygen, Conductivity, Salinity, TDS, and Temperature Sampling Handheld Meter


MultiLab IDS 4320 Conductivity and Temperature Sensor

Conductivity and temperature, Stainless Steel body, 2-electrodes, digital probe, 1.5 meter cable


IQ SensorNet TetraCon® Sensors

Submersible Conductivity probe for IQ System, requires cable assembly

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EXO Wiped Conductivity & Temperature Sensor

EXO Wiped Conductivity & Temperature Digital Smart Sensor

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