Capacitor (or capacitance, Capacitance) refers to the charge in the reserves under a given potential difference; referred to as C, international farads (F). Generally, the charge will be the force to move in an electric field, when with the media, hinders the charge transfer between the conductor and makes the charge accumulation on the conductor; cause accumulated storage charges, the most common example of this is two parallel metal board. Also known as the capacitor.

 

 

  Defined capacitance (or capacity) is the ability to characterize the physical quantity charge capacitor accommodating. We put the potential difference between the plates of the capacitor increases 1 volt of electricity needed, called the capacitance of the capacitor. Capacitor from the physics perspective, it is a static electric charge storage medium (like a bucket, as you can charge into the charge in the absence of the discharge circuit [1] case, excluding medium leakage self-discharge effect / electrolysis capacitance is obvious, the charge may permanent, which is its features), and its wider use, it is electronic, electrical fields indispensable electronic components. Mainly used for power supply filtering, signal filtering, signal coupling, resonance, DC blocking other circuits. The symbol is the capacitance C. C = εS / d = εS / 4πkd (vacuum) = Q / U in the international system of units, the capacitance in farads, referred to France, the symbol F, commonly used capacitive units millifarad (mF), microfarad (μF ), mobility method (nF), and picofarads (pF) (also known as pico picofarads method), conversion relationship is: 1 farad (F) = 1000 millifarad (mF) = 1000000 microfarads (μF) 1 micro method ( μF) = 1000 nanofarads (nF) = 1000000 picofarads (pF).

Related formula

  A capacitor, if with a library of electricity potential levels between the difference is 1 V, the capacitance of the capacitor is a law, namely: C = Q / U but the size of the capacitor than by Q (with battery) or U (voltage) decision, namely: C = εS / 4πkd. Where, ε is a constant, S is the area of the capacitor plates is on, d is the distance between the capacitor plates, k is the constant of static electricity. Common parallel plate capacitor, capacitance C = εS / d (ε is the dielectric constant of the medium between the plates, S is the plate area, d is the distance between the plates.) The electrical potential capacitor formula:. E = CU ^ 2/2 = QU / 2 多 capacitors in parallel formula: C = C1 + C2 + C3 + ... + Cn multiple capacitors in series formula: 1 / C = 1 / C1 + 1 / C2 + ... + 1 / Cn three capacitors in series C = (C1 * C2 * C3) / (C1 * C2 + C2 * C3 + C1 * C3)

Capacitance electrostatic field

  Capacitance is the ability to hold an electric field. Any static electric field is made up of many capacitors, electrostatic field, there capacitors, capacitance electrostatic field is described. Generally considered: isolated conductor and infinity form a capacitor, equivalent to the grounding conductor connected to infinity, and integrally connected with the earth need to use a variety of electronic production of capacitors, which are different plays in the circuit role. Similar to the resistor, typically referred to as a capacitor, indicated by the letter C. As the name suggests, the capacitor is the "charge storage container." Although capacitor variety, but their basic structure and principles are the same. Two pieces of metal are in close proximity in the middle of a substance (solid, gas or liquid) are separated, constitute a capacitor. Two metal plates called middle substance called media. Capacity capacitor is also divided into fixed and variable capacity. But common is fixed capacity capacitor, the most common electrolytic capacitors and ceramic capacitors. Ability of different charge storage capacitor is not the same. Providing for the amount of charge a capacitor plus 1 volt DC voltage stored in the capacitance of the capacitor is called. The basic unit of capacitance is Farad (F). But in fact, Farah is a very common unit, because the capacity of the capacitor is often much less than 1 farad, commonly microfarads (μF), mobility method (nF), picofarads (pF) (also known skin slightly Law Act ), etc., their relationship is: 1 farad (F) = 1000000 microfarads (μF) 1 microfarad (μF) = 1000 nanofarads (nF) = 1000000 picofarads (pF) in electronic circuits, capacitors are used through the exchange while blocking DC, it is also used to store and release charge to act as a filter, the smooth output ripple signal. Small-capacity capacitor, typically used in high-frequency circuits, such as radios, transmitters and oscillators. Large-capacity capacitor is often used for filtering and storage charges. And there is a feature, usually more than 1μF capacitors are electrolytic capacitors, and 1μF less capacitance ceramic capacitors, mostly, of course, there are also other, such as monolithic capacitors, polyester capacitors, small capacity mica capacitors. There aluminum electrolytic capacitors, filled with electrolyte, and leads to two electrodes, as a positive (+) and negative (-) terminals, and other capacitors different, polarity in the circuit can not be wrong, while the other capacitors are There is no polarity. The two electrodes of the capacitor are connected to the power of positive and negative electrode, then, even if the power is turned off, there will still be two pins between residual voltage (after school tutorials, you can use a multimeter observation), we said capacitor storage charge. Establish a voltage between the capacitor plates, savings from energy, a process called charge the capacitor. Both ends of the capacitor charged a certain voltage. Capacitors store electric charge to process circuit release, known as the capacitor discharges. For a real-life example, we see a commercially available rectifier power supply after unplugging the above light-emitting diodes will continue for a while, then gradually extinguished, because inside the energy storage capacitor in advance, and then released. Of course, this was originally used as a filtering capacitor. As capacitor filter, I wonder if you have not listened Walkman experience with rectifier power supply, generally low quality of power supply due to the cost savings for manufacturers to consider using a smaller capacity filter capacitor, causing the headset buzz. Then you can across the power supply and connected to a large-capacity electrolytic capacitor (1000μF, pay attention to the positive then positive), the general effect can be improved. HiFi stereo enthusiasts making, should use more of at least 10,000 microfarads capacitor filter, the greater the filter capacitor, the voltage waveform output closer to DC, and the role of large capacity storage, making sudden arrival of large-signal chip capacitors , the circuit has enough energy into powerful audio output. In this case, the role of a bit like a large capacitor reservoir, making the original turbulent flow smoothly output, and can guarantee the supply of water when a large number of downstream. Electronic circuits, only in the capacitor charging process, current flows through only after the end of the charging process, the capacitor is not by DC, acts as a "DC blocking" role in the circuit. Circuits, capacitors are often used as coupling, bypass, filtering, etc., are using it, "through exchanges, DC blocking" features. Why alternating current through the capacitor can then do? Let's take a look at the AC characteristics. AC alternating back and forth not only the direction, its size also changes according to the law. A capacitor connected to the AC power supply, the capacitor is continuously charged and discharged, the circuit will flow through the AC consistent variation (different phases) of the charge and discharge currents. Selection of the capacitor involves many issues. The first is the problem of pressure. Plus the voltage across a capacitor exceeds its rated voltage, the capacitor will be breakdown. General electrolytic capacitor voltage binning of 6.3V, 10V, 16V, 25V, 50V, etc. [2]

[Edit this paragraph] capacitor type designation

  Domestic capacitor models generally consists of four parts (not applicable to pressure-sensitive, variable vacuum capacitors). In turn represent the name, materials, classification and serial number.

first part:

  Name, with letters, capacitor C.