Talk:Electrical conductivity meter

How does it actually work?

From what I can tell from using one of these, it measures the voltage across a pair of plates and calculates the conductivity based on the geometry. I found it strange that there is no mention of how it actually works in the article. This is probably in the wrong section because it's more of a request,but this is my first edit so just let me know. Swhanna (talk) 14:45, 8 August 2008

I agree (add that to the article if you want). I didn't try to describe it since there is more than one way these could work and I'm no expert on ec-meters, just wanted to provide a useful description of what it is. Although I suspect what you describe is the most straightforward and most common design.
—Apis (talk) 02:37, 20 November 2008 (UTC)

Temperature dependence

Units for sigma T and sigma Tcal are not stated. Maybe originator should update? 203.37.186.106 (talk) 21:23, 19 November 2007 (UTC)

Well the sigmas, σ_T and σ_Tcal, cancel each other so it doesn't really matter what unit is used. I forgot to specify the unit for α (alfa) in the table though which may have caused some confusion since it was in %/°C. I changed the values to 1/°C and made that clear. It is also fine to use fahrenheit for temperature, but then the numbers in the table would be wrong so that's why I mention what unit to use for temperature. (Celsius or Kelvin are SI units so thats why they are used in the table). Thanks for pointing it out though, wouldn't have thought of this otherwise. --Apis O-tang (talk) 16:56, 10 April 2008 (UTC)

Actually changed it back to %/°C but made it clearer. Apis (talk) 18:41, 6 May 2008 (UTC)

I think the formula as it is currently given is wrong. The conductivity of a solution should increase with temperature, but in the formula:

$\sigma _{T}={\sigma _{T_{cal}}/[1+\alpha (T-T_{cal})]}$

$\sigma _{T}$ decreases as T increases (for positive $\alpha$). Philgp (talk) 15:05, 24 June 2010 (UTC)

After looking through the page's history, it seems that the original form was:

$\sigma _{T}={\sigma _{T_{cal}}[1+\alpha (T-T_{cal})]}$

and the insertion of the division sign was possibly vandalism. I've reverted it.Philgp (talk) 15:25, 24 June 2010 (UTC)

Thanks for your careful correction. It is, in my opinion, correct. About the "vandalism", I learned to assume good faith, also for anonymous contributors. The current text could be improved by exchanging the sides of the conductivity at 25 deg C is (the calculated value) with that of the conductivity at non-standard temperature, and giving a reference. I found the following references which are conveniently web-accessible . Also, the value for nitric acid seems off scale so I will tag it with the "fact" template unless somebody verifies it with a Horiba reference, which provides more expected value. Sorry I cannot make the changes myself. Cheers. Stan J. Klimas (talk) 18:37, 25 June 2010 (UTC)

What is the measurement unit?

The article doesn't mention what physical units are used to state the conductivity. Some documents seem to give the conductivity in "EC Values". What is that in physical terms? is it milli Siemens (mS) or what? --Stefanhanoi (talk) 13:16, 7 November 2019 (UTC)

In the formula, the parameter α represents a ratio between two different conductivities. Therefore, as far as conductivity is concerned, it is dimensionless and does not require a conductivity unit.---Ehrenkater (talk) 13:34, 7 November 2019 (UTC)

More generally, quoted EC values state the units used, such as microsiemens per centimetre (μS cm^-1) or whatever.---Ehrenkater (talk) 13:41, 7 November 2019 (UTC)

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