The origin of the electrolytic capacitor before and you say ah, ah characteristics of thin film capacitor. Etc.. These are established in these capacitors function. But in fact, we do not understand the nature of capacitor. What is theessence of today and we talk about the capacitor.

We start with the assumption that a and B two placed parallel to a conducting plate, interval between them with an insulating material such as air like, then in the middle of a switch S is connected to a direct-current source E. When the two plates are not connected to power supply before they are not charged for the neutral state. When the switch is turned on, a plate of electronic was drawn to the positive pole of a battery, so a will become a positively charged phenomenon; at the same time the negative battery terminal negative electron was rejected to the plate B, so that B shows the phenomenon of negative charge; and a, B between the two plates in the formation of electric field and the establishment of a potential difference v. This flow of electrons, by transfer of power and the power supply voltage is proportional to, until the AB two electrode potential difference equal to the supply voltage (v = e) didn't stop electronic mobile. The process flow of electrons, the energy band and the power dump in thepolar plate, that is to say the charge storage.

As mentioned above, two parallel plate conductive segment with an insulating material is stored charge capacity of equipment, called a capacitor or on). The conductive plate is called electrode capacitor (electrode), known as a dielectric insulating material (dielectric) or medium.

Capacitance (capacitance) is used to represent the ability of a capacitor to save charge (or capacity). A variety of capacitors, because of different conductor size shape body material and plate distance and medium types and other factors and different capacitance, but stored charge Q and potential V is proportional to the

Q=CV

The proportion of C type is in constant capacitance capacitor capacitor, referred to as.

C=Q/V

The unit of capacitance for "library / volts, to commemorate the scientist Michael Faraday (Michael Faraday l791 to 1867 Britain on electricity great contribution, one Coulomb per volt capacitor said 1 farad (farad), referred to as the law, unit mark for the f or F. In practice, farad unit often too big, such as a sphere if 1 farad capacitance, radius must meters 9*10e9! So often in the micro method (F) or mmfd (mu F or pF) to represent the capacitance.

Two parallel plate capacitor is the most simple and practical capacitor, in between the two plates filled with medium, the two plates separated d even less than in the area a, as shown below. The area and medium size and metal plate capacitance of the dielectric coefficient is proportional, and inversely proportional to the distance between two plates, i.e.

C= (A) /d

Vacuum or air dielectric coefficient epsilon =8.84*10e-12 (F/m).

Good. Here you may hear the nature for the capacitor also know vaguely. This is normal. Because often the nature is theory and practice is the sole criterion for testing truth, after all, can be a lot of attention to this knowledge to understand today essence used in the above is the correct attitude towards learning.