Thursday 2 February 2012

Basic Capacitor Guide

Basic Capacitor

Capacitors: Capacitors are passive electronic components widely used in electronic circuits, they are used in the source filter circuit, noise, signal ac circuit, oscillator circuit. Etc. ...
1. Components of the capacitor.
Components of the capacitor consists of two parallel plates, in the middle of an insulating layer called the dielectric.
People often use paper, ceramic, mica, paper impregnated with chemicals as capacitor dielectrics and also classified under the name of the capacitor dielectric as paper, ceramic capacitors, Capacitor



                                                Structure composed of ceramic capacitors
 


2. Actual shape of the capacitor.

The shape of the ceramic capacitors.
The shape of the convergence of
3. Capacitance, units and symbols of the capacitor.
* Capacity: A measure of the ability to speak on two charged plates of the capacitor, the capacitance of the capacitor depends on the area of plates, dielectric material and the distance keeping the two plates by the formula
C = ξ. S / d
  • In the C: is the capacitance capacitor units are FARA (F)
  • ξ: A dielectric constant of the insulating layer.
  • d: the thickness of the insulating layer.
  • S: is the area of ​​the capacitor plates.
* Capacitance of the capacitor units: Unit is FARA (F), 1Fara was great in practice so common as the smaller units MicroFara (μF), NanoFara (nF), PicoFara (pF).
  • FARA FARA μ 1 = 1,000,000 = 1,000,000,000 = 1,000,000,000,000 n F p F
  • 1 μ FARA FARA n = 1000
  • 1 n = 1,000 p FARA FARA
* Symbol: Capacitors are denoted as C (capacitor)
Symbols of the capacitor on the principle diagram.
 


4. The charging of the capacitor discharge.
An important property of the capacitor is charging the capacitor discharge characteristics, thanks to the nature of this convergence is likely to lead AC.
Illustration of the nature of the load capacitor discharge.
* Capacitor charging: As the image above we see that, when the switch K1 closed, electric current passing from U to the lamp load capacitor, a charge is made ​​flashing lights, when the load capacitor is fully charged down equal to 0 so the lights off.
* Capacitor discharge: When the capacitor has fully charged, if the open switch K1, K2 switch closed, the current from the positive (+) of the capacitor discharge through the lamp on the negative (-) as flashing lights, when gathering the ball full potential power lights off.
=> If the capacitor capacitance becomes larger, the flashing lights as long or longer charging times larger.
5. How to Read the capacitance value of capacitor.
* As of: The value of the capacitance of the capacitor is recorded directly on the relative convergence
=> Gathering of the capacitors have polarity (-), (+) and are always cylindrical.
Capacitor of 185 μF is the capacitance recording / 320 V
* The paper capacitors, ceramic capacitors: capacitor paper and ceramic capacitors with values ​​written in symbols
Ceramic capacitor values ​​recorded by the symbol.
  • How to read: For the first two digits of the 10 (Hat number 3)
  • For example, the right ceramic capacitor 474K image recording means
    Value = 47 x 10 4 = 470,000 p (in units of pico Get FARA)
    FARA = 470 n = 0.47 μF
  • K or J at the end is only 5% error or 10% of the capacitor.
* Do read the value of the capacitor.

How to read capacitor values ​​laundry and ceramic capacitors.
Note: The letter K is the error of convergence.
50V is the maximum voltage that capacitor tolerance.
* Paper and ceramic capacitors also have a way to treat others as stated in decimal units and get MicroFara
A record number of capacitors of paper and ceramic capacitors.
6. The idea of the value of capacitor voltage indicated on the body:
  • We see that regardless of how well the capacitor voltage values ​​recorded immediately after the capacitance value, this is the maximum voltage value that convergence tolerance, the capacitor voltage will be explosive.
  • When inserted into a circuit capacitor voltage is U, then it is never mounted capacitor voltage value of about 1.4 times higher than Max.
  • For example, to mount capacitor circuit 12V 16V, 24V circuit must be fitted 35V capacitor. etc. ..
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7 - Classification of capacitor
7.1) of paper capacitors, ceramic capacitors, mica capacitors. (Capacitors are not polarized)
The convergence of this kind regardless of Yin and Yang and often have small capacitance of 0.47 μF or less, the capacitors are often used in high frequency circuits or circuit noise.

Ceramic capacitor - a capacitor is not polarized.
7.2) magnetized (polarized capacitors)
Convergence of the positive and negative equity, convergence of a larger value and values ​​from 0.47 μF to 4700 μF range, convergence chemical commonly used in low frequency circuits or for power filters, convergence of cylindrical always ..
Convergence of - is a negative-positive polarity.
7.3) rotate.
Capacitors can turn the focus turning to change the capacitance value, capacitor is usually mounted in the radio to change the resonant frequency when you tune.
Capacitors used in radio rotation
8 - Method of test capacitors
8.1) Measurement of test paper and ceramic capacitors.
Paper capacitors and ceramic capacitors are usually in the form of broken or leak has been short, for leak detection or been short convergence we observe the following image.
Measure the test paper or ceramic capacitors.
  • The image above is checked ceramic capacitor measurements, three capacitors C1, C2 and C3 have equal capacitance, the capacitor C1 is that good, the capacitor C2 and C3 detectors are capacitors has been short.
  • When measuring capacitor C1 (from good) to a slightly larger needle then return to previous position. (Note the small focus too <1nF load, the needle will not release)
  • When measuring capacitor C2 (capacitor detectors), we see the needle on the scale halfway and stopped does not return to previous position.
  • When measuring the capacitor C3 (Capacitor been short) = 0 we see the needle on Ω and not return.
  • Note: When measuring or checking the paper capacitors ceramic capacitors we have to clock in or x10KΩ x1KΩ scale, and to the island clockwise several times after that.
8.2) Measurement of test capacitors
Magnetized detectors or rarely been short as capacitor paper, but they dry out or damage in the form (dry chemicals inside the dielectric layer) to the capacitance of the capacitor is reduced, to check the convergence of, we often compare magnification of capacitor loaded with a good convergence with the same capacitance, the following picture illustrates the convergence of these tests.
Measurement of convergence test
  • To check capacitor values ​​of 100μF C2 is the capacitance can be reduced or not, we use the new capacitor C1 also has the same capacitance and measurement comparisons.
  • To watch in scale from x1Ω to x100Ω (the larger the capacitance to the lower scale)
  • Measure and compare the two capacitor charging zoom, then the measuring stick we reversed several times.
  • If two capacitor discharge capacitor load is equally good to check in on our reporter that loaded less capacitor C2 capacitor C2 so on have been dry.
  • Where the needle back up without a capacitor detector.
Note: If the test capacitor directly on the circuit, we need to draw from an empty vessel in a vacuum capacitors, then tested as above.
9 - The types of problems and applications
9.1. Capacitors connected in series.
  • The capacitor in series with the equivalent capacitance C TD is calculated by the formula: 1 / C td = (1 / C1) + (1 / C2) + (1 / C3)
  • Where only two capacitors connected in series, the C td = C1.C2 / (C1 + C2)
  • When connected in series, the withstand voltage of the capacitor voltage equal to the sum of the capacitor combined. TD U = U1 + U2 + U3
  • When the capacitor connected in series, if it is the focus of attention should be paid dimensions of the capacitor, the negative first capacitor connected to the positive capacitor follows:
Capacitors connected in series capacitor in parallel
09.02 - Capacitors in parallel.
  • The capacitor in parallel with the capacitance, the equivalent total capacitance of the capacitor combined. C = C1 + C2 + C3
  • Withstand voltage of the capacitor voltage was roughly equal with the lowest voltage capacitor.
  • If the capacitor of the capacitor must be connected in the same way Yin and Yang.
9.3 - Application of the capacitor.
Capacitors are used in many electrical and electronic engineering, in electronics, the capacitor is an indispensable component, each circuit has a certain utility as signal transmission, interference filters, power filters, oscillators, etc. .. ...
Here are some pictures illustrating the application of capacitors.
* Filter capacitors in the power circuit.
Capacitor filter circuit of the source.
  • The source filter circuit as shown above, convergence of effective filter for DC voltage after the rectifier is to provide a flat load consumption, we see if there is no DC capacitor voltage after the diode voltage undulating, when the filter capacitor voltage is relatively flat, the larger the capacitor DC voltage is more flat.
* Capacitors in the oscillator circuit to two square pulse.
Multi-body oscillator circuit using two transistors
  • You can mount on the circuit parameters given in the diagram.
  • Two bright lights use LEDs in parallel with the polar CE mark of the second transistor,

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