Farad - wikipedia Farad For other uses, see Farad ( disambiguation ). Farad A one farad modern super-capacitor. The scale behind is in inches ( top ) and centimetres. Unit information Unit system SI derived unit Unit of Capacitance Symbol F Named after Michael Faraday In SI base units : s ⋅ A ⋅ m ⋅ kg The farad ( symbol : F ) is the SI derived unit of electrical capacitance, the ability of a body to store an electrical charge. It is named after the English physicist Michael Faraday. Contents 1 Definition 1.1 Equalities 2 History 3 Explanation 3.1 Informal and deprecated terminology 3.2 Related concepts 4 CGS units 5 See also 6 Notes 7 External links Definition One farad is defined as the capacitance across which, when charged with one coulomb, there is a potential difference of one volt. Equally, one farad can be described as the capacitance which stores a one - coulomb charge across a potential difference of one volt. The relationship between capacitance, charge and potential difference is linear. For example, if the potential difference across a capacitor is halved, the quantity of charge stored by that capacitor will also be halved. For most applications, the farad is an impractically large unit of capacitance. Most electrical and electronic applications are covered by the following SI prefixes : 1 mF ( millifarad, one thousandth ( 10 ) of a farad ) = 1000 μF = 1000000 nF 1 μF ( microfarad, one millionth ( 10 ) of a farad ) = 0.000 001 F = 1000 nF = 1000000 pF 1 nF ( nanofarad, one billionth ( 10 ) of a farad ) = 0.001 μF = 1000 pF 1 pF ( picofarad, one trillionth ( 10 ) of a farad ) Equalities A farad is represented in terms of SI base units as s ⋅ A ⋅ m ⋅ kg It can further be expressed as : F = C V = A ⋅ s V = J V 2 = W ⋅ s V 2 = N ⋅ m V 2 = C 2 J = C 2 N ⋅ m = s 2 ⋅ C 2 m 2 ⋅ kg = s 4 ⋅ A 2 m 2 ⋅ kg = s Ω = 1 Ω ⋅ Hz = s 2 H, ( displaystyle ( \text ( F ) ) = ( dfrac ( \text ( C ) ) ( \text ( V ) ) ) = ( dfrac ( ( \text ( A ) ) ( cdot ) ( \text ( s ) ) ) ( \text ( V ) ) ) = ( dfrac ( \text ( J ) ) ( ( \text ( V ) ) ^ ( 2 ) ) ) = ( dfrac ( ( \text ( W ) ) ( cdot ) ( \text ( s ) ) ) ( ( \text ( V ) ) ^ ( 2 ) ) ) = ( dfrac ( ( \text ( N ) ) ( cdot ) ( \text ( m ) ) ) ( ( \text ( V ) ) ^ ( 2 ) ) ) = ( dfrac ( ( \text ( C ) ) ^ ( 2 ) ) ( \text ( J ) ) ) = ( dfrac ( ( \text ( C ) ) ^ ( 2 ) ) ( ( \text ( N ) ) ( cdot ) ( \text ( m ) ) ) ) = ( dfrac ( ( \text ( s ) ) ^ ( 2 ) ( cdot ) ( \text ( C ) ) ^ ( 2 ) ) ( ( \text ( m ) ) ^ ( 2 ) ( cdot ) ( \text ( kg ) ) ) ) = ( dfrac ( ( \text ( s ) ) ^ ( 4 ) ( cdot ) ( \text ( A ) ) ^ ( 2 ) ) ( ( \text ( m ) ) ^ ( 2 ) ( cdot ) ( \text ( kg ) ) ) ) = ( dfrac ( \text ( s ) ) ( Omega ) ) = ( dfrac ( 1 ) ( Omega ( cdot ) ( \text ( Hz ) ) ) ) = ( dfrac ( ( \text ( s ) ) ^ ( 2 ) ) ( \text ( H ) ) ), ) where F = farad, A = ampere, V = volt, C = coulomb, J = joule, m = metre, N = newton, s = second, W = watt, kg = kilogram, Ω = ohm, Hz = hertz, H = henry. History The term `` farad '' was originally coined by Latimer Clark and Charles Bright in 1861, in honor of Michael Faraday, for a unit of quantity of charge but by 1873, the farad had become a unit of capacitance. In 1881 at the International Congress of Electricians in Paris, the name farad was officially used for the unit of electrical capacitance. Explanation Examples of different types of capacitors A capacitor generally consists of two conducting surfaces, frequently referred to as plates, separated by an insulating layer usually referred to as a dielectric. The original capacitor was the Leyden jar developed in the 18th century. It is the accumulation of electric charge on the plates that results in capacitance. Modern capacitors are constructed using a range of manufacturing techniques and materials to provide the extraordinarily wide range of capacitance values used in electronics applications from femtofarads to farads, with maximum - voltage ratings ranging from a few volts to several kilovolts. Values of capacitors are usually specified in farads ( F ), microfarads ( μF ), nanofarads ( nF ) and picofarads ( pF ). The millifarad is rarely used in practice ( a capacitance of 4.7 mF ( 0.0047 F ), for example, is instead written as 4700 μF ), while the nanofarad is uncommon in North America. The size of commercially available capacitors ranges from around 0.1 pF to 5000F ( 5 kF ) supercapacitors. Parasitic capacitance in high - performance integrated circuits can be measured in femtofarads ( 1 fF = 0.001 pF = 10 F ), while high - performance test equipment can detect changes in capacitance on the order of tens of attofarads ( 1 aF = 10 F ). A value of 0.1 pF is about the smallest available in capacitors for general use in electronic design, since smaller ones would be dominated by the parasitic capacitances of other components, wiring or printed circuit boards. Capacitance values of 1 pF or lower can be achieved by twisting two short lengths of insulated wire together. The capacitance of the Earth 's ionosphere with respect to the ground is calculated to be about 1 F. Informal and deprecated terminology The picofarad is sometimes colloquially pronounced as `` puff '' or `` pic '', as in `` a ten - puff capacitor ''. Similarly, `` mic '' ( pronounced `` mike '' ) is sometimes used informally to signify microfarads. If the Greek letter μ is not available, the notation `` uF '' is often used as a substitute for `` μF '' in electronics literature. A `` micro-microfarad '' ( μμF, and confusingly often mmf or MMF ), an obsolete unit sometimes found in older texts, is the equivalent of a picofarad. In texts prior to 1960, and on capacitor packages even much more recently, `` mf '' or `` MFD '' rather than the modern `` μF '' frequently represented microfarads. Similarly, `` mmf '' or `` MMFD '' represented picofarads. Related concepts The reciprocal of capacitance is called electrical elastance, the ( non-standard, non-SI ) unit of which is the daraf. C.G.S. units The abfarad ( abbreviated abF ) is an obsolete CGS unit of capacitance equal to 10 farads ( 1 gigafarad, GF ). The statfarad ( abbreviated statF ) is a rarely used CGS unit equivalent to the capacitance of a capacitor with a charge of 1 statcoulomb across a potential difference of 1 statvolt. It is 1 / ( 10 c ) farad, approximately 1.1126 picofarads. See also Capacitor Supercapacitor Orders of magnitude ( capacitance ) Notes Jump up ^ The International System of Units ( SI ) ( PDF ) ( 8th ed. ). Bureau International des Poids et Mesures ( International Committee for Weights and Measures ). 2006. p. 144. Jump up ^ Peter MB Walker, ed. ( 1995 ). Dictionary of Science and Technology. Larousse. ISBN 0752300105. Jump up ^ As names for units of various electrical quantities, Bright and Clark suggested `` ohma '' for voltage, `` farad '' for charge, `` galvat '' for current, and `` volt '' for resistance. See : Latimer Clark and Sir Charles Bright ( 1861 ) `` On the formation of standards of electrical quantity and resistance, '' Report of the Thirty - first Meeting of the British Association for the Advancement of Science ( Manchester, England : September 1861 ), section : Mathematics and Physics, pp. 37 - 38. Latimer Clark and Sir Charles Bright ( November 9, 1861 ) `` Measurement of electrical quantities and resistance, '' The Electrician, 1 ( 1 ) : 3 -- 4. Jump up ^ Sir W. Thomson, etc. ( 1873 ) `` First report of the Committee for the Selection and Nomenclature of Dynamical and Electrical Units, '' Report of the 43rd Meeting of the British Association for the Advancement of Science ( Bradford, September 1873 ), pp. 222 - 225. From p. 223 : `` The `` ohm, '' as represented by the original standard coil, is approximately 10 C.G.S. units of resistance ; the `` volt '' is approximately 10 C.G.S. units of electromotive force ; and the `` farad '' is approximately 1 / 10 of the C.G.S. unit of capacity. '' Jump up ^ ( Anon. ) ( September 24, 1881 ) `` The Electrical Congress, '' The Electrician, 7 : 297. From p. 297 : `` 7. The name farad will be given to the capacity defined by the condition that a coulomb in a farad gives a volt. '' Jump up ^ Tunbridge, Paul ( 1992 ). Lord Kelvin : his influence on electrical measurements and units. London : Peregrinus. pp. 26, 39 -- 40. ISBN 9780863412370. Retrieved 5 May 2015. Jump up ^ Braga, Newton C. ( 2002 ). Robotics, Mechatronics, and Artificial Intelligence. Newnes. p. 21. ISBN 0 - 7506 - 7389 - 3. Retrieved 2008 - 09 - 17. Common measurement units are the microfarad ( μF ), representing 0.000, 001 F ; the nanofarad ( nF ), representing 0.000, 000,001 F ; and the picofarad ( pF ), representing 0.000, 000,000,001 F. Jump up ^ Platt, Charles ( 2009 ). Make : Electronics : Learning Through Discovery. O'Reilly Media. p. 61. ISBN 9781449388799. Retrieved 2014 - 07 - 22. Nanofarads are also used, more often in Europe than in the United States. Jump up ^ Gregorian, Roubik ( 1976 ). Analog MOS Integrated Circuits for Signal Processing. John Wiley & Sons. p. 78. Jump up ^ Pease, Bob ( 2 September 1993 ). `` What 's All This Femtoampere Stuff, Anyhow ? ''. Electronic Design. Retrieved 2013 - 03 - 09. Jump up ^ Pease, Bob ( 1 December 2006 ). `` What 's All This Best Stuff, Anyhow ? ''. Electronic Design. Retrieved 2013 - 03 - 09. Jump up ^ Williams, L.L. ( January 1999 ). `` Electrical Properties of the Fair - Weather Atmosphere and the Possibility of Observable Discharge on Moving Objects '' ( PDF ). Retrieved 2012 - 08 - 13. Jump up ^ `` Puff ''. Wolfram Research. Retrieved 2009 - 06 - 09. Jump up ^ `` 1940 Catalog - Page 54 - Capacitors ( Condensers ) ''. RadioShack. Archived from the original on 11 July 2017. Retrieved 11 July 2017. Jump up ^ `` Daraf ''. Webster 's Online Dictionary. Archived from the original on 2011 - 10 - 04. Retrieved 2009 - 06 - 19. Jump up ^ Graf, Rudolf F. ( 1999 ). Modern Dictionary of Electronics. Newnes. p. 1. ISBN 9780080511986. Retrieved 2016 - 04 - 15. External links Farad unit conversion tool SI units Authority : International System of Units ( BIPM ) Base units ampere candela kelvin kilogram metre mole second Derived units with special names becquerel coulomb degree Celsius farad gray henry hertz joule katal lumen lux newton ohm pascal radian siemens sievert steradian tesla volt watt weber Other accepted units astronomical unit bar dalton day decibel degree of arc electronvolt hectare hour litre minute minute of arc neper second of arc tonne atomic units natural units See also Conversion of units Metric prefixes Proposed redefinitions Systems of measurement Book Retrieved from `` https://en.wikipedia.org/w/index.php?title=Farad&oldid=851647528 '' Categories : SI derived units Units of electrical capacitance Michael Faraday Hidden categories : Pages using deprecated image syntax Talk Contents About Wikipedia Aragonés Asturianu Azərbaycanca Беларуская Беларуская ( тарашкевіца ) ‎ Български བོད ་ ཡིག Bosanski Català Čeština Cymraeg Dansk Deutsch Eesti Ελληνικά Español Esperanto Euskara فارسی Français Gaeilge Galego 한국어 Հայերեն हिन्दी Hrvatski Bahasa Indonesia Íslenska Italiano עברית ქართული Қазақша Latviešu Lietuvių Magyar Македонски മലയാളം Монгол Nederlands 日本 語 Nordfriisk Norsk Norsk nynorsk Occitan پنجابی Piemontèis Polski Português Română Русиньскый Русский Scots Shqip Sicilianu Simple English Slovenčina Slovenščina Српски / srpski Srpskohrvatski / српскохрватски Suomi Svenska தமிழ் Татарча / tatarça ไทย Türkçe Українська اردو Tiếng Việt 粵語 中文 62 more Edit links This page was last edited on 23 July 2018, at 17 : 43 ( UTC ). 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Question: what is the meaning of uf in capacitor
Answer: microfarad, one millionth (10−6) of a farad