All types of capacitors
Types of Capacitors : There are three types of capacitors as listed below :
Parallel Plate Capacitor : If two parallel metallic plates of equal area A are separated by a distance d. One plate carries a charge Q , and the other carries a charge –Q. Let us consider how the geometry of these conductors influences the capacity of the combination to store charge. Recall that charges of same sign repel one another. As a capacitor is being charged by a battery, electrons flow into the negative plate and exist out of the positive plate. If the capacitor plates are large, the accumulated charges are able to distribute themselves over a substantial area, and the amount of charge that can be stored on a plate for a given potential difference increases as the plate area is increased. Thus, we expect the capacitance to be proportional to the plate area A. Hence the capacitance of a parallel plate capacitor depends only on the geometry of the capacitor but not on the charge on the capacitor and potential difference between the plates.
Cylindrical Capacitor : A special type of parallel plate capacitor in which the insulating dielectric layer is rolled up between the plates. A cylindrical capacitor is made up of a conducting cylinder or wire of radius a surrounded by another concentric cylindrical shell of radius b where b > a. In this type of capacitor a cylindrical conductor having linear charge density +λ is surrounded by a coaxial cylindrical conducting shell having charge density –λ. Due to attraction between unlike charges, the charges will be spread out uniformly on the outer surface of the inner conductor and the inner wall of the outer conductor. The capacitance of a cylindrical capacitor, depends only on the geometrical factors like length of the cylinder and the radius of the two coaxial cylindrical conductors.
Capacitors on a Motherboard of a Desktop
Spherical Capacitor : A spherical capacitor is formed by two concentric conducting spheres. Let's assume that the inner sphere has an outer radius r1, charge +q and the outer sphere has an inner radius r2 and charge –q. The electric field is perpendicular to the surface of both spheres and points radially outward. All the capacitors, like batteries, store energy to be used at a later time. But unlike a standard battery, they deliver quick, intense bursts of energy. As a result, capacitors can withstand significantly more charge and discharge cycles than batteries and can deliver more power at a time. Capacitors can even be used with batteries.