Information AboutFarad |
| CATEGORIES ABOUT FARAD | |
| si derived units | |
| units of electrical capacitance | |
| SHOPPER'S DELIGHT | |
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The farad (symbol: F) is the SI unit of Capacitance . DEFINITION A Capacitor has a value of one farad when one Coulomb of stored Charge causes a Potential Difference of one Volt across its terminals. Its equivalent expression in SI Base Unit s is: :. SI MULTIPLES EXPLANATION Since the farad is a very large unit, values of Capacitor s are usually in range of microfarads (μF), nanofarads (nF), or picofarads (pF). The picofarad is comically called a "puff" in laboratory usage. The millifarad is rarely used in practice, so that a capacitance of 4.7 F, for example, is usually written as 4700 μF. Very small capacitance values, such as those used in Integrated Circuit s may also be expressed in femtofarads, one femtofarad being equal to 1 F. A new technology called Supercapacitor s offers devices up to the kilofarad range. The farad should not be confused with the Faraday , an old unit of charge nowadays superseded by the coulomb. The reciprocal of capacitance is called Electrical Elastance , the (non-standard, non-SI) unit of which is the Daraf . A Capacitor 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 Charge on the plates that results in Capacitance . Modern Capacitor s are constructed using a range of manufacturing techniques and materials to provide the extraordinary wide range of capacitance values used in practical Electronics applications from femtofarads to farads and voltage withstand capabilities from a few Volt s to a several kV. |