en>Addbot: Bot: Migrating 1 interwiki links, now provided by Wikidata on d:q5060045

2013-03-17T01:53:28Z

Bot: Migrating 1 interwiki links, now provided by Wikidata on d:q5060045

← Older revision		Revision as of 03:53, 17 March 2013
Line 1:		Line 1:
	~~Wilber Berryhill~~ is ~~what his wife enjoys~~ to ~~contact him~~ and ~~he completely loves this name~~. ~~Her family life~~ in ~~Ohio~~ but ~~her spouse desires them~~ to ~~move~~. ~~Office supervising~~ [http://~~cspl~~.~~postech~~.ac.kr/~~zboard~~/~~Membersonly~~/~~144571 free psychic readings~~] ([http://~~findyourflirt~~.~~net~~/~~index~~.~~php~~?m=~~member_profile~~&p=~~profile~~&id=~~117823 findyourflirt~~.~~net~~]~~) is where her main earnings comes from but she's already applied for another one~~. ~~What me and my family members love is to climb but I'm thinking on beginning some thing new~~.~~<br><br>Look into my web~~-~~site~~ - ~~online psychics~~ ([http://~~Netwk~~.~~hannam~~.ac.kr/xe/~~data_2~~/~~85669 additional hints~~])		{{Unreferenced\|date=September 2011}}
			[[Image:Electrical conductivity meter.jpg\|thumb\|250px\|An electrical conductivity meter.]]

			An '''electrical conductivity meter''' ('''EC meter''') measures the [[conductivity (electrolytic)\|electrical conductivity]] in a [[solution]]. It is commonly used in [[hydroponics]], [[aquaculture]] and [[freshwater]] systems to monitor the amount of nutrients, salts or impurities in the water.

			== Principle ==
			The common laboratory conductivity meters employ a potentiometric method and four electrodes. Often, the electrodes are cylindrical and arranged concentrically{{Citation needed\|date=September 2011}}. The electrodes are usually made of platinum metal. An alternating current is applied to the outer pair of the electrodes. The potential between the inner pair is measured{{Citation needed\|date=September 2011}}. Conductivity could in principle be determined using the distance between the electrodes and their surface area using the [[Ohm's law]] but generally, for accuracy, a calibration is employed using electrolytes of well-known conductivity.

			Industrial conductivity probes often employ an inductive method, which has the advantage that the fluid does not wet the electrical parts of the sensor. Here, two inductively-coupled coils are used. One is the driving coil producing a magnetic field and it is supplied with accurately-known voltage. The other forms a secondary coil of a transformer. The liquid passing through a channel in the sensor forms one turn in the secondary winding of the transformer. The induced current is the output of the sensor.

			== Temperature dependence ==
			{{main\|Electrical conductivity#Temperature dependence\|l1=Electrical conductivity}}
			The conductivity of a solution is highly [[temperature]] dependent, therefore it is important to either use a temperature compensated instrument, or calibrate the instrument at the same temperature as the solution being measured. Unlike metals, the conductivity of common electrolytes typically increases with increasing temperature.

			Over a limited temperature range, the way temperature affect conductivity ''of a solution'' can be modeled [[linear]]ly using the following formula:
			:<math>\sigma_T = {\sigma_{T_{cal}}[1 + \alpha (T - T_{cal})] }</math>

			where
			:''T'' is the temperature of the sample,
			:''T<sub>cal</sub>'' is the calibration temperature,
			:''σ<sub>T</sub>'' is the electrical conductivity at the temperature ''T'',
			:''σ<sub>T<sub>cal</sub></sub>'' is the electrical conductivity at the calibration temperature ''T<sub>cal</sub>'',
			:''α'' is the temperature compensation slope of the solution.

			The temperature compensation slope for most naturally occurring [[water]]s is about 2%/°C, however it can range between 1 to 3%/°C. The compensation slope for some common [[Aqueous solution\|water solutions]] are listed in the table below.
			{\| class="wikitable"
			\|-
			! [[Aqueous solution]] at 25 [[Celsius\|°C]]
			! Concentration ([[Mass fraction (chemistry)\|mass percentage]])
			! α (%/°C)
			\|-
			\|[[Hydrochloric acid\|HCl]]
			\|10
			\|1.56
			\|-
			\|[[Potassium chloride\|KCl]]
			\|10
			\|1.88
			\|-
			\|[[Sulfuric acid\|H<sub>2</sub>SO<sub>4</sub>]]
			\|50
			\|1.93
			\|-
			\|[[Sodium chloride\|NaCl]]
			\|10
			\|2.14
			\|-
			\|[[Hydrofluoric acid\|HF]]
			\|1.5
			\|7.20
			\|-
			\|[[Nitric acid\|HNO<sub>3</sub>]]
			\|31
			\|31
			\|}

			==See also==
			{{commonscat\|Electrical conductivity meters}}
			*[[Conductivity factor]]
			*[[Electrical conductivity]]
			*[[Salinometer]]
			*[[Total dissolved solids]]
			*[[TDS meter]]

			==External links==
			*[http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4414366&userType=inst IEEE paper telling how a four electrode meter works]
			*[http://www.analyticaltechnology.com/cms/LinkClick.aspx?fileticket=H6s0PzX1oXQ%3d&tabid=56&mid=456 Sales literature telling how a four electrode meter works]
			*A webpage by [[Horiba]] telling about [http://www.horiba.com/application/material-property-characterization/water-analysis/water-quality/ph-knowhow/the-story-of-conductivity/the-fundamentals/temperature-compensation/ temperature compensation]
			*[http://books.google.com/books?id=6jhELyGJOm0C&pg=PA497&dq=compensation+of+electrolyte+conductivity+temperature&hl=en&ei=M_EkTJOfDsL48AaHkunXDw&sa=X&oi=book_result&ct=result&resnum=1&ved=0CC4Q6AEwAA#v=onepage&q=compensation%20of%20electrolyte%20conductivity%20temperature&f=false A book which includes a discussion of temperature compensation]
			*Cole–Parmer [http://www.coleparmer.com/techinfo/techinfo.asp?htmlfile=Conductivity.htm&ID=78 article on conductivity and conductivity meters]
			*[http://www.millipore.com/lab_water/clw4/tutorial&tabno=3 Milli-Q System High Precision Coaxial Resistivity Cell]
			*[http://www.astm.org/Standards/D1193.htm ASTM D1125 - 95(2009) Standard Test Methods for Electrical Conductivity and Resistivity of Water]
			*[http://www.astm.org/Standards/D5682.htm ASTM D5682]
			*[http://www.beuth.de/de/norm/din-55667/113260432 DIN 55667]

			[[Category:Electrochemistry]]
			[[Category:Measuring instruments]]

en>Entropeneur: /* Application */ Added another application example.

2012-08-02T16:30:46Z

Application: Added another application example.

New page

Wilber Berryhill is what his wife enjoys to contact him and he completely loves this name. Her family life in Ohio but her spouse desires them to move. Office supervising [http://cspl.postech.ac.kr/zboard/Membersonly/144571 free psychic readings] ([http://findyourflirt.net/index.php?m=member_profile&p=profile&id=117823 findyourflirt.net]) is where her main earnings comes from but she's already applied for another one. What me and my family members love is to climb but I'm thinking on beginning some thing new.<br><br>Look into my web-site - online psychics ([http://Netwk.hannam.ac.kr/xe/data_2/85669 additional hints])

Centering matrix - Revision history

en>Addbot: Bot: Migrating 1 interwiki links, now provided by Wikidata on d:q5060045

en>Entropeneur: /* Application */ Added another application example.