View：86　Time：2016-09

Thin film capacitor, the essence of capacitor

Before and we said the origin of the electrolytic capacitor, ah, the characteristics of the film capacitor ah. Wait。 These are based on the function of these capacitors. But in fact, we do not understand the nature of the capacitor. Today, we will talk about the nature of the capacitor.
We first assume that there are two blocks of A and B parallel placement of the conductive plates, they are two of the middle of the interval to insulation material such as air, and then the middle with a switch S connected to the DC source E. When the two plate is not connected to the power supply before they are to maintain a neutral state. When the switch is opened, the electronic plate A was attracted to the anode of the battery, and A showed a positively charged phenomenon; at the same time the negative electron battery negative terminals are exclusive to plate B, B showed a negatively charged phenomenon; then between A and B two electrode electrically to establish a potential field and differential V. This phenomenon of electronic flow continues, the transfer of power and the power supply voltage is proportional to the difference between the AB two electrode and the power supply voltage is equal (V = E), to stop the movement of electrons. In the process of electron flow, the energy of the electric power is brought out and transferred to the bipolar plate, which is to say that the charge is stored.
As mentioned above, the two parallel conductive plates are separated by an insulating material and a device having the ability to store electric charge, called a capacitor (capacitor or condenser). Electrode (electrode), which is called the electrode of capacitor (), is called dielectric (dielectric) or short medium.
Capacitance (capacitance) is used to represent the capacity of the capacitor to charge the savings (or capacity). All kinds of capacitors, because of the size of the conductor and the plate material and the distance between the different types of media and other factors, there is not the same amount of capacitance, but the amount of charge can be stored Q and its potential V is proportional to the
Q=CV
The ratio constant C in the formula is the capacitance of the capacitor.
C=Q/V
The unit of capacitance is the "library" to commemorate / V, scientist Faraday (Michael Faraday l791 - 1867, UK) a great contribution to the electrical capacitance of 1 volts, called 1 Coulomb / Fala (farad), referred to as the law, unit is F or F mark. In practical, the unit of Fala is often too large, such as a ball to 1 Fala's capacitance, the radius must be 9*10e9 meter! Therefore, the micro method (F) or micro method (F or pF) is used to indicate the size of the capacitor.
Two parallel metal plate capacitor is the most simple and practical capacitor, between the two boards to fill the medium, between the two plates of D is much smaller than the area of the plate 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 the two plates, i.e.
C= (A) /d
Vacuum or air dielectric coefficient epsilon =8.84*10e-12 (F/m).
Okay。 Here you may hear the nature for the capacitor also know vaguely. This is normal. Because nature is often theory, and practice is the only criterion for testing truth, we can pay more attention to this piece of knowledge, the nature of today's understanding of the above is the correct attitude towards learning.