Capacitance(Capacitor)

Capacitors are those given under the charge of erps reserves; Notes for C, international unit is ferrari (F). Generally speaking, charge in the electric field in will stress and mobile, when the conductor between medium, is hindered charge mobile has accumulated in conductors in charge, The cumulative storage caused charge, the most common example is two parallel plates. Also called capacitors.

introduction

definition

Capacitance (or called capactance) is characterized for charge ability of physical measurement of capacitor. We put the capacitor plates between the two DianShiCha increase of one volt required power, called the capacitor capacitance. Capacitor physics suggests, it is a kind of static charge storage medium (like a bucket, you can take charge filling save, without discharge circuit [1] circumstances, BaoChu medium leakage self-discharge effects/electrolytic capacitors is quite obvious, may charge will permanently existence that is its characteristics), its purpose wider, it is the electron, the electric power field indispensable electronic components. Mainly used for power filtering, signal filtering, signal coupling, resonant, lie between dc circuits, etc.

Capacitance symbol is C.

C = search-evade antagonistic S/d = search-evade antagonistic S / 4 PI kd (vacuum) = Q/U

In the international system of units, capacitance unit is a ferrari, abbreviation method, symbol is the F, commonly used capacitance unit has baekho method (mF), micro method (u F), natrium method (nF) and leather method (0.8pf) (skin method is also called slightly method), the conversion relation is:

1 ferrari (F) = 1000 baekho method (mF) = 1,000, 000 micro method (u F)

1 small method (u F) = 1000 natrium method (nF) = 1,000, 000 skin method (0.8pf).

Related formula

A capacitor, if take 1 library power between the two levels DianShiCha is 1 volts, the capacitor capacitance is one method, i.e. : C = Q/U but capacitance than by the size of the qq (with electricity) or U (voltage) to decide, namely: the search-evade antagonistic S/C = 4 PI kd. Among them, the search-evade antagonistic is a constant, S for capacitance plate facing the area, d for capacitance plate distance, k is static electricity constants. Common parallel plate capacitor, capacitance for C = search-evade antagonistic S/d. (search-evade antagonistic for plate between medium dielectric constant, S for plate area, d for plate in the distance between).

Define type C = Q/U

Capacitors of electric can calculation formula: E ^ 2 = CU / 2 = QU / 2

Many capacitor parallel calculation formula: C = C1 + C2 + C3 +... + Cn

Many capacitor series formula: 1 / C = 1 / C1 + 1 / C2 +... + 1 / Cn

Three capacitor series C = (C1 * * C2 / C3) (C1 * C2 + C2 * C3 + C1 * C3)

Capacitance and electrostatic field

Capacitance refers to the ability to accommodate electric field. Any electrostatic field is composed by many capacitance, electrostatic field there capacitance, capacitance is described with electrostatic field. Generally think: isolated conductor to infinity is constitute capacitance, conductor grounding equivalent to receive infinity, and with the earth connected into the whole

Electronic production needs to use the various capacitor, they respectively in a circuit plays a different role. And resistor similar, commonly referred for its capacitance, with the letter "C" said. Just as its name implies, capacitors is "stored charge of containers". Although capacitor varities, but their basic structure and principles are the same. Two houses are close by a substance among the metal (solids, gas or liquid) separated by, they form a capacitor. Two pieces of metal plate, the intermediate called material called medium. Capacitors are capacity of fixed and capacity variable. But common is fixed size of capacitance, most seen is electrolytic capacitors and ceramics capacitors.

Different capacitors to store charge ability is not identical also. Stipulates the capacitor plus one volt dc voltage when the stored charge quantity is called the capacitor electric capacity. The basic unit of capacitance for ferrari (F). But in fact, ferrari is a very common unit because the capacitor capacity often than 1 ferrari much smaller, commonly used micro method (u F), natrium method (nF), skin method (0.8pf) (skin method is also called slightly method) and so on, their relationship is: 1 ferrari (F) = 1,000, 000 micro method (u F) 1 small method (u F) = 1000 natrium method (nF) = 1,000, 000 skin method (0.8pf)

In electronic circuits, capacitance used to cut through communication and dc, and also used to store and release charge to act as filters, smooth output pulse signal. Small capacity of capacitance, usually in high-frequency circuits using, such as radio, transmitter and oscillators. High-capacity capacitor is often make filtering and storage charge use. There is also a characteristic, general 1 u F above the capacitance are electrolytic capacitors, and 1 u F below the capacitance more for ceramics capacitor, certainly also have other, such as multilayer ceramic capacitor, polyester capacitor, small capacity of mica capacitance, etc. Electrolytic capacitors have a aluminium shell and filled with the electrolyte, and drawn two electrodes, as positive (+), negative (-) extremely, with other capacitor differently, they cannot meet the polarity in circuit fault, and other capacitance is no polarity.

The capacitors connected the two electrode respectively the positive and negative power, even if the power after a while, two pins disconnect between there will still be residual voltage (learned later tutorials, can using a multimeter to observe), we say capacitors to store the charge. Capacitor plates, establish the voltage between savings on electricity, the process is called capacitor recharge. Filling good electrical capacitor ends have certain voltage. Capacitors to store the charge to release process, called circuit of capacitors discharge.

Heave a real-life examples, we see the functionalities of rectifying power supply in the drawing of plug, above light-emitting diodes (leds) will continue to shine for a moment, then gradually quenched, is because inside the capacitance prior storage power, and then release. Of course this was originally used to filter capacitance. As for capactance filtering, did you have a try rectifying power supply to listen to a walkman experience, general inferiority of power supply manufacturer for cost saving due to consider using a smaller capacity filter capacitance, causing the headset has buzz. At both ends and connected to the power can be in a large capacity electrolytic capacitors (1000 u F, pay attention to the positive connect the positive, it can improve the effect. Enthusiasts HiFi sound production, all want to use at least 1 million micro method above capacitors filtering, filter capacitance, the greater the output voltage waveform approximates to dc and large capacitance of energy storage effect, make emergency patch capacitance

The large signal arrival, circuit has enough energy conversion for powerful audio output. At this moment, big capacitance role a bit like reservoir, makes it turbulent flow smoothly output, and can ensure the supply of large when water downstream.

In electronic circuits, only in the capacitor recharge process, just have the currents, charging process ended, the dc capacitor is cannot pass, in a circuit plays "lie between dc" action. A circuit, capacitors were often used as a coupling, bypass, filtering, are using it "tong exchanges, separate dc" feature. So why can pass capacitor alternating current? Now let's look at the characteristics of alternating current. Ac alternating direction, it not only reciprocating size also is in at regular changes. Capacitor in communication power supply, capacitors continuously charging, discharge, circuit will change laws are consistent with alternating current flows through different phase.quantum) (charging electric current and discharge current.

Capacitor's choosing involves a lot of problems. First is compression. Add in a capacitor at both ends of the voltage ahead of its rated voltage capacitor will be breakdown damage. General electrolytic capacitors of changeover divides class 6.3 V, 10V, 16V, 25V 50V etc.,

Capacitor model naming methods

Homebred capacitor models are usually made of four parts (applicable to pressure-sensitive, variable, and vacuum capacitor). Ordinal respectively represent name, materials, classification and serial number.

First part:

Name, with letters express, capacitors in C.

Part two:

Material, using letters.

Part 3:

Classification, general use numerals, individual with letters.

Part four:

Serial number, numerically.

Use letters show that products of materials: A - tantalum electrolysis, B - polystyrene nonpolar film, C - high frequency ceramic, D - aluminum electrolysis, E - other materials electrolysis, the G alloy electrolysis, H - compound medium, I to glass glaze, J - metallized paper, L - polyester, etc polarity organic film, N - niobium electrolysis, O - glass film, Q - film, T - low-frequency ceramics, V - mica paper, Y and Z - - mica paper