How Capacitors Work

 Capacitors are electronic components that can store electrical charges. The structure of a capacitor made of 2 pieces of metal plates separated by a dielectric material
Electric materials are commonly known as air vacuum, ceramic, glass and others. If both ends of the metal plate was given voltage, the positive charges will accumulate on one leg (electrode) metal and at the same time the negative charges accumulated on the metal edges of one another.
 

The positive charge can not flow toward the negative pole and the opposite end of the negative charge can not be heading back up the positive pole, because the dielectric material separated by a non-conductive.

Electric charge is "stored" as long as no conduction at the ends of the legs. In the wild, this phenomenon occurs when the capacitor charge accumulation-positive and negative charges in the clouds. That is a brief overview of how the workings of capacitors.

Capacitance 
Capacitance is defined as the ability of a capacitor to hold charge of the electron. Coulombs in the 18th calculate that 1 coulomb = 6.25 x 1018 electrons. Then Michael Faraday made postulate that a capacitor will have a capacitance of 1 farad when a voltage 1 volt can load as many as 1 electron charge coulombs. With the formula can be written:

Q = CV ... ... ... ... .... (1)
Q = electron charge in C (coulombs)C = the capacitance in F (farads)V = the voltage in V (volts)

For the series of practical electronics, the unit of farads is very huge. Generally, the capacitor that is in the market has units of UF (10-6 M), nF (10-9 M) and pF (10-12 F). Conversion unit is important for ease of reading the amount of a capacitor. For example 0.047uF can also be read as a 47nF, or other examples similar to 100pF 0.1nF

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
 Electrostatic capacitors are a group of capacitors that 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 the dielectric film material is a material such as polyester (polyethylene terephthalate, or known as Mylar), polystyrene,polyprophylene, polycarbonate, metalized paper and others.Mylar, MSM, 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 Capacitors
 Electrolytic capacitor group consisting of the capacitors dielectric materials are metal-layer capacitors oksida.Umumnya including this group is a polar capacitor dengantanda + and - in the body. Why are these capacitors can have a polarity, is due to the manufacturing process uses electrolysis to form the positive pole anode and cathode negative pole

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. example of this capacitor is Elco / condenser.
Oxidation layer is formed through a process of electrolysis, as in the process of gold plating. Metal electrode is dipped into the solution electrolit (sodium borate) and given a positive voltage (anode) and the solution given electrolit negative voltage (cathode). Oxygen in electrolyte solution apart and mengoksidai metal plate surface. For example, if used Aluminum, it will form a layer of aluminum-oxide (Al2O3) on the surface.

Thus successive metal plate (anode), layer-metal-oxide and the electrolyte (cathode) form a capacitor. In this layer-metal-oxide as the dielectric. Metal-oxide layer is very thin, and thus can be made large enough capacitance capacitors. Due to economical and practical reasons, generally a lot of metal material used is aluminum and tantalum. The material most widely and cheaply is Aluminium. To get a broad surface, 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. Tantalum capacitor electrolyte material in a liquid there but there is also a solid. Called the solid electrolyte, but it is not the solution electrolit its negative electrode, but other materials are manganese-dioxide. Thus this type of capacitors can have large capacitance, but becoming more slender and petite. Also because of all the solid, then their work time (lifetime) to be more durable.Capacitors of this type also has a very small leakage current can be understood why so Tantalum capacitors become relatively expensive.

3.Electrochemical Capacitors
 One other type of capacitor is an electrochemical capacitor. Including this type of capacitors are batteries and batteries. In fact the battery and capacitor batteries is very good, because it has a large capacitance and leakage current (leakage current) is very small. This type of capacitors of this type are also still in development to get a large capacitance, but small and light, for example for electric cars and mobile application provider.
Electrochemical Capacitors One other type of capacitor is an electrochemical capacitor. Including this type of capacitors and batteries are the batteries. In fact the battery and capacitor batteries is very good, because it has a large capacitance and leakage current (leakage current) is very small. This type of capacitors of this type are also still in development to get a large capacitance, but small and light, for example for electric cars and mobile application provider.

Capacitor Tolerance
As with other components, there are large nominal capacitance tolerance. The table below presents the values of tolerance with codes specific numbers or letters.

With this table the user can easily know the tolerance of capacitors which usually accompany the printed face value capacitors. For example, if a written 104 X7R, then kapasitasinya is 100nF with a tolerance of + / -15%. At the same time also note that the recommended working temperature is between-55C to +125 C, the calculation is not easy. In practice if we find the values of tolerance of a capacitor which is smaller then the price will be more expensive as well.