Capacitors: Lesson 4 PDF

 Define capacitance, charge, and potential difference in capacitors. Explain the role of dielectrics in modifying capacitance and reducing electric field strength. Solve the equivalent capacitance, charge on individual capacitor and potential differences acros...

 Define capacitance, charge, and potential difference in capacitors. Explain the role of dielectrics in modifying capacitance and reducing electric field strength. Solve the equivalent capacitance, charge on individual capacitor and potential differences across them.  A device used to store electric charge, used in various applications like radio reception filtering and heart defibrillator energy storage. It typically has two conducting parts, separated by an insulator. When battery terminals are connected, the capacitor stores a charge Q. a. Parallel Plate Capacitors b. A rolled capacitor with an insulating material between its two conducting sheets.  The amount of charge Q a capacitor can store depends on Thetwo major voltage factors: applied The capacitor’s physical characteristics, such as its size.  A system of two parallel conducting plates separated by distance. The voltage and stored charge are related through an electric field line, with more lines for more charges. The electric field strength is directly  The ability of capacitor to store charges. In Symbols: C = Capacitance of a capacitors q = Amount of charge in one plate V = Potential Difference between the plate/  The unit of capacitance is the farad (F). Named for Michael Faraday (1791–1867), an English scientist who contributed to the fields of electromagnetism and electrochemistry. 1. The area of plates. The bigger the area of the plates, the greater the capacitance. 2.The distance between the plates. The closer the plates to each other, the greater the capacitance. 3.The insulating material or dielectric between them. The capacitance determined in terms of the materials permittivity constant ε - the higher the ε, the greater the  Has two identical plates with surface areas A and d, separated by a distance d. It stores a charge Q when applied to a voltage. The capacitance depends on A and d, with larger plates storing more charge and closer plates A = area of one plate in square meters d = distance between the plates in meters ε0 = permittivity of free space ε0 = 8.85 × 10^−12 Permittivity of Some Common Dielectrics Paraffin 2 ε (x10^-11 Dielectric C^2/N.m) Polyethylene 1.99 Air or Vacuum 0.886 Porcelain 6.2 Glass (Ordinary) 7 Glass (pyrex) 4.7 Teflon 1.9 Mica 4.8 Water at 20°C 70.8 Mylar 2.7  A capacitor consist of two square metal plates, each measuring 5.0 x 10^- 2 m on a side. In between the plates is a sheet of mica measuring 1.00 x 10^-4 m thick. (a) What is the capacitance of this capacitor? If the charge in one plate is 2.00 x 10^-8 1. The parallel plates of an air capacitor are separated by 2.25mm. Each plate carries a charge of 6.50 nC. The magnitude of the electric field of the plate is 4.5x10^5 V/m. Find the a) capacitance of the  The total capacitance (CT) of a circuit is equal to the sum of all individual capacitors added together. The top plates of capacitors are connected, increasing the effective plate area. The capacitance value of the combination increases as it is related to plate area (C = ε(A/d). The total capacitance of parallel capacitors is calculated by adding the plate area together. The total capacitance of parallel capacitors is found similarly to the total resistance of series resistors.  Each capacitor in a series combination acquires an identical charge when connected to a battery. Charges are induced on other plates, resulting in zero sum of charges on all plates and any pair of capacitor plates. Potential drop on one capacitor may differ from another due to different capacitances. A series combination of two or three capacitors resembles a single capacitor with smaller capacitance. Any number of capacitors connected in series is equivalent to one with smaller capacitance than the smallest of the series combination. All capacitors of a series combination have the same charge due  Find the total capacitance for three capacitors connected in series, given their individual capacitances are 1.000, 5.000, and 8.000 µF.  A dielectric is an insulating material, such as glass, plastic, or ceramic, that doesn't conduct electricity easily. Key characteristic: It can be polarized, meaning the positive and negative charges within the material can be slightly separated Polarization: When a dielectric is placed between the plates of a capacitor, the electric field from the plates causes the molecules in the dielectric to polarize. Positive charges in the dielectric align slightly towards the negatively charged plate. Negative charges in the dielectric align slightly towards the positively charged plate.  Reduced Electric Field: This polarization creates an internal electric field within the dielectric that opposes the external field from the capacitor plates. Increased Charge Storage: To maintain the same voltage across the capacitor, more charge must be stored on the plates to overcome the opposing internal field. This effectively increases the capacitance.  As explained above, the polarization of the dielectric creates an internal electric field that opposes the external field. This reduces the overall electric field strength between the capacitor plates.