Weston cell


Weston cell

The Weston cell, invented by Edward Weston in 1893, is a wet-chemical cell that produces a highly stable voltage suitable as a laboratory standard for calibration of voltmeters. It was adopted as the International Standard for EMF in 1911.

Chemistry

The anode is an amalgam of cadmium with mercury, the cathode is of pure mercury, the electrolyte is a solution of cadmium sulfate and the depolarizer is a paste of mercurous sulfate.

As shown in the illustration, the cell is set up in an H-shaped glass vessel with the cadmium amalgam in one leg and the pure mercury in the other. Electrical connections to the cadmium amalgam and the mercury are made by platinum wires fused through the lower ends of the legs.

Characteristics

The original design was a saturated cadmium cell producing a convenient 1.0183 Volt reference and had the advantage of having a lower temperature coefficient than the previously used Clark cell. (Reference cells must be applied in such a way that no current is drawn from them.)

The temperature coefficient can be reduced by shifting to an unsaturated design, the predominant type today. However, an unsaturated cell's output decreases by some 80 microvolts per year, which is compensated by periodical calibration against a saturated cell.

Patent

*, "Voltaic cell"

ee also

* Primary cell terminology

ources

* "Practical Electricity" by W. E. Ayrton and T. Mather, published by Cassell and Company, London, 1911, pp 198-203

External links

* [http://humboldt.edu/~scimus/Instruments/Elec-Duff/StdCellDuff.htm Standard Cells]
* [http://www.allaboutcircuits.com/vol_1/chpt_11/4.html Special-purpose batteries]


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  • Weston cell — Vestono elementas statusas T sritis chemija apibrėžtis 1,0183 V įtampos elementas Cd(Hg)|CdSO₄|Hg₂SO₄, Hg (25°C). atitikmenys: angl. Weston cell rus. элемент Вестона …   Chemijos terminų aiškinamasis žodynas

  • Weston cell — noun a standard voltaic cell (trademark Weston) • Syn: ↑cadmium cell • Usage Domain: ↑trademark • Hypernyms: ↑standard cell * * * Trademark. a brand of cadmium cell. Also called Weston standard cell …   Useful english dictionary

  • Weston cell — Trademark. a brand of cadmium cell. Also called Weston standard cell. * * * …   Universalium

  • Weston cell — /wɛstən ˈsɛl/ (say westuhn sel) noun a type of primary cell used as a standard of electric potential, consisting of mercury and cadmium electrodes in a saturated solution of cadmium sulphate; produces 1.0183 volts at 20°C. Also, cadmium cell …   Australian English dictionary

  • Weston — NOTOC There are many places called Weston:People: For people named Weston, see Weston (surname). PlacesAustralia* Weston, Australian Capital Territory * Weston Park, Canberra * Weston, New South WalesBorneo (Sabah)* Weston, SabahCanada* Weston,… …   Wikipedia

  • Weston normal cell — etaloninis kadmio elementas statusas T sritis radioelektronika atitikmenys: angl. cadmium standard element; Weston normal cell vok. Kadmiumnormalelement, n; Weston Normalelement, n rus. кадмиевый нормальный элемент, m; нормальный элемент Вестона …   Radioelektronikos terminų žodynas

  • Weston normal cell — norminis Vestono elementas statusas T sritis fizika atitikmenys: angl. Weston normal cell vok. Weston Normalelement, n rus. нормальный элемент Вестона, m pranc. pile Weston, f …   Fizikos terminų žodynas

  • Weston-Normalelement — etaloninis kadmio elementas statusas T sritis radioelektronika atitikmenys: angl. cadmium standard element; Weston normal cell vok. Kadmiumnormalelement, n; Weston Normalelement, n rus. кадмиевый нормальный элемент, m; нормальный элемент Вестона …   Radioelektronikos terminų žodynas

  • Weston-Normalelement — norminis Vestono elementas statusas T sritis fizika atitikmenys: angl. Weston normal cell vok. Weston Normalelement, n rus. нормальный элемент Вестона, m pranc. pile Weston, f …   Fizikos terminų žodynas

  • Edward Weston (chemist) — Infobox Person name = Edward Weston image size = caption = birth name = birth date = May 9, 1850 birth place = Oswestry, Shropshire, England death date = August 20, 1936 death place = Montclair, New Jersey death cause = resting place = resting… …   Wikipedia


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