Part Number All Omega search term

Technical Conductivity and Resistivity

Conductivity measures the ability of a solution to conduct an electric current between two electrodes. In solution, the current flows by ion transport. Therefore, with an increasing amount of ions present in the liquid, the liquid will have a higher conductivity. If the number of ions in the liquid is very small, the solution will be "resistive" to current flow. AC current is used to prevent complete ion migration to the two electrodes.

Conductance = 1/Resistance

Conductivity: mho = Siemen
Normal unit of measurement is:
1 micromho (µmho) = 1 microSiemen (µS),
1 millimho (mmho) = 1 milliSiemens (mS) = 1,000 µS

Resistivity: ohm
Normal unit of measurement is:
megohm = 1,000,000 ohm

Example - Conductivity to Resistivity Conversion:
Conductivity:

= 20 µS
= 20 x 10-6 S
= 2 x 10-5 S
= 2 x 10-5 mho

Resistivity:
1 ohm/2 x 10-5

= 1/conductivity
= 1/2 x 10-5 ohm
= 0.5 x 10-5 ohm
= 5 x 10 4 ohm

Conductivity and Resistivity (NaCl and CaCO3 Solutions at 25°C)

 ppm as CaCO3 ppm NaCl Conductivity micromhos/cm Resistivity megohm-cm 1700 2000 3860 0.00026 1275 1500 2930 0.00034 850 1000 1990 0.00050 425 500 1020 0.00099 170 200 415 0.0024 127.5 150 315 0.0032 85.0 100 210 0.0048 42.5 50 105 0.0095 17.0 20 42.7 0.023 12.7 15 32.1 0.031 8.5 10 21.4 0.047 4.25 5.0 10.8 0.093 1.70 2.0 4.35 0.23 1.27 1.5 3.28 0.30 0.85 1.00 2.21 0.45 0.42 0.50 1.18 0.88 0.17 0.20 0.49 2.05 0.13 0.15 0.38 2.65 .085 0.10 0.27 3.70 0.042 0.05 0.16 6.15 0.017 0.02 0.098 10.2 0.012 0.015 0.087 11.5 0.008 0.010 0.076 13.1 0.004 0.005 0.066 15.2 0.002 0.002 0.059 16.9 0.001 0.001 0.057 17.6 none none 0.055 18.3

Probe Constants
Probe constant defines the volume between the electrodes. Solutions with an extremely high conductivity require a sensor with a probe constant greater than 1.0. Solutions with extremely low conductivity require a sensor with a probe constant less than 1.0. The greater the distance between the electrodes, the smaller the current signal.

 Conductivity (Micromhos/cm) Resistivity (Ohms-cm) Dissolved Solids (ppm) .056 18,000,000 .0277 .084 12,000,000 0.417 .167 6,000,000 0.833 1.00 1,000,000 .500 2.50 400,000 1.25 20.0 50,000 10.0 200 5000 100 2000 500 1,000 20,000 50 10,000
 © Copyright 2003-2017  |  OMEGA ENGINEERING, Inc. | OMEGA Privacy Statement  |  Terms and Conditions MXV MMV | 78