Water Conductivity Measurement Circuit

Water up to 3 ms cm can be consumed though most drinking tap water is below 0 8 ms cm.

Water conductivity measurement circuit. Its unit is cm 1. Thus the measure of a water sample s electrical conductivity is a function of its ionic impurity concentration. Unit of measurement of conductance is siemens s. Conductivity is traditionally determined by connecting the electrolyte in a wheatstone bridge.

This ability is directly related to the concentration of ions in the water 1. Conductivities below 10 µsiemens cm. Resistivity is expressed in ω cm and conductivity is expressed in s cm ms cm or μs cm. But easy to see changes when a pinch of salt was added to the water endgroup george herold mar 23 15 at 13 22.

Ultra pure water has a conductivity of 0 055 µsiemens cm or a resistivity of 18 18 mω cm at 25 c. Conductivity is therefore an important analytical measurement for certain water purity applications such as the treatment of boiler feedwater and the preparation of high purity water used for semiconductor manufacturing. High quality deionized water has a conductivity of about 0 5 μs cm at 25 c typical drinking water is in the range of 200 800 μs cm while sea water is about 50 ms cm or 50 000 μs cm. Ac drive voltage ss probes in water tia opamp circuit to measure the current.

The measurement of conductivity depends on the cell constant which is a function of the length surface and geometry of the electrode. Well the hard part is the calibration. The cell constant c is the current response of a sensor on account of sensor dimensions and geometry. In order to know the conductivity or resistivity of ultra pure water it is required to do accurate temperature compensation at very low conductivities e g.

These conductive ions come from dissolved salts and inorganic materials such as alkalis chlorides sulfides and carbonate compounds 3. Aqueous conductivity is commonly expressed in millisiemens cm ms cm and natural waters range from 0 05 1 5 ms cm for freshwater lakes streams up to about 55ms cm for sea water. Adding electrolytes such as salts acids or bases to pure water increases the conductance and decreases resistance. Circuit description the circuit shown in figure 3 is a completely self contained microprocessor controlled highly accurate conductivity measurement system that is ideal for measuring the ionic content of liquids water quality analysis industrial quality control and chemical analysis.

I made a little circuit for measuring water conductivity a few months ago.