DC CircuitsCAPACITANCECapacitanceCapacitance is the ability to store an electrical charge. Capacitance is equal to the amount ofcharge that can be stored divided by the applied voltage, as shown in Equation (3-7).C = (3-7)QVwhereC = capacitance (F)Q = amount of charge (C)V = voltage (V)The unit of capacitance is the farad (F). A farad is the capacitance that will store one coulombof charge when one volt is applied across the plates of the capacitor.The dielectric constant (K) describes the ability of the dielectric to store electrical energy. Airis used as a reference and is given a dielectric constant of 1. Therefore, the dielectric constantis unitless. Some other dielectric materials are paper, teflon, bakelite, mica, and ceramic.The capacitance of a capacitor depends on three things.1. Area of conductor plates2. Separation between the plates3. Dielectric constant of insulation materialEquation (3-8) illustrates the formula to find the capacitance of a capacitor with two parallelplates.C = (3-8)K^{A}d(8.85 x 10^{12})whereC = capacitanceK = dielectric constantA = aread = distance between the plates8.85 x 10^{-12}= constant of proportionalityRev. 0 Page 11 ES-03

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