capacitor

capacitor is an electrical component that serves to store electrical charges. One type of capacitor is keeping parallel capacitor. This capacitor consists of two parallel pieces of metal separated by an insulator called a dielectric. When the capacitor is connected to a battery-charged capacitor until the potential difference between the two terminals with battery voltage. If the battery is removed, electric charges will be exhausted in a very long time, except when a conductor is connected to the two capacitor terminals.

Capacitor Type
The capacitor consists of several types, depending on the dielectric material. For more simple can be divided into 3 parts, namely electrostatic capacitors, electrolytic and electrochemical.

1. Electrostatic capacitor is a capacitor groups are made with a dielectric material of ceramic, film and mica. Ceramic and mica is a popular material and cheap to make small capacitance capacitors. Quantities available from pF to several UF, which is usually for a series of applications relating to high frequency. Groups including film dielectrics are materials such as polyester (polyethylene terephthalate, or known as Mylar), polystyrene, polyprophylene, polycarbonate, metalized paper and others. Mylar, MKM, MKT are some examples of the trademark name for the capacitor with a dielectric material film. Generally this group of capacitors is the non-polar.
2. Electrolytic capacitor group consisting of the capacitors dielectric materials are metal-oxide layer. Generally capacitor including this group is a polar capacitor with the + and - in the body. Why are these capacitors can have a polarity, is due to the manufacturing process uses electrolysis to form positive negative pole, anode pole and cathode. It has long been known for some metals such as tantalum, aluminum, magnesium, titanium, niobium, zirconium and zinc (zinc) surface can be oxidized to form metal-oxide layer (oxide film). Oxidation layer is formed through the process of electrolysis, as in the gold plating process. Metal electrodes are dipped into a solution electrolit (sodium borate) and given a positive voltage (anode) and the solution given electrolit negative voltage (cathode). Oxygen in electrolyte solution and oxidize the surface apart metal plate. For example, if you use aluminum, it will form a layer Aluminum-oxide (Al2O3) on the surface.
   
   Elco capacitor
   Thus successive metal plate (anode), layer-metal-oxide and the electrolyte (cathode) form a capacitor. In this layer-metal-oxide as the dielectric. From formula (2) great unknown capacitance is inversely proportional to the thick dielectric. Metal-oxide layer is very thin, so that the capacitor can be made large enough capacitance. Because of economical and practical reasons, generally a lot of metal material used is aluminum and tantalum. Materials and the most expensive is Aluminum. To obtain a large surface, this aluminum plate material is usually rolled radially. So in a way that can be obtained large capacitance capacitors. For example 100uF, 470uF, 4700uF and others, which often also called capacitor elco. Electrolyte materials on Tantalum capacitor is a liquid, but there is also a solid. Called the solid electrolyte, but it is not the solution to be electrolit its negative electrode, but other materials are manganese-dioxide. Thus this type of capacitors can have large capacitance, but became more slender and petite. Also because of all the solid, then their work time (lifetime) to be more durable. This type of capacitor has a leakage current is very small so can be understood why Tantalum capacitors become relatively expensive.
3. electrochemical capacitor including batteries and batteries are very good, because it has a large capacitance and leakage current (leakage current) is very small. This type of capacitor types are also still in development for a large capacitance, but small and light, for example for electric car application and mobile phone.