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A capacitor (also called condenser, which is the older term) is an electronic device that stores electric energy. It is similar to a battery, but is smaller, lightweight and charges up much quicker. Capacitors are used in many electronic devices today, and can be made out of many different types of material.
Capacitors are usually made with two metal plates that are on top of each other and near each other, but that do not actually touch. When powered, they allow energy to be stored inside an electrical field. Because the plates need a lot of area to store even a small amount of charge, the plates are usually rolled up into some other shape, such as a cylinder. Sometimes, other shapes of capacitors are used for special purposes. A capacitor-like effect can also result just from two conductors being close to each other, whether you want it to exist or not.
All capacitors have two connections, or leads. Most kinds of capacitors can be changed around easily by someone who has basic skills in electronics. However, one of the more powerful types - the electrolytic capacitor - must be used the correct way, or they can explode violently.
While capacitors do have similarities to batteries in that they can store energy - as mentioned earlier - capacitors can also release all their stored energy very quickly, even faster than a second. Batteries, on the other hand, release their energy slowly.
A charging and discharging defibrillator for heart attacks is a good example of how a capacitor gradually charges up, until it can not be filled any more, and then quickly discharging its stored power to another area that needs it to function.
Supercapacitors hold more of a charge than regular capacitors and will discharge faster. They won't be found in a TV or computer.
Polystyrene film capacitors [change]
This type of capacitor is not for use in high frequency circuits, they are constructed by the a coil inside it. They are used well in filter circuits or timing circuits which run at several hundred KHz or less.
Electrolytic capacitors [change]
A electrolytic capacitor is polarized and they have to be attached in the correct way. There are two leads and one will have a + and the other a -. There are two different designs of capacitors axial: where the leads are connected to both ends and the radial where the leads are connected to one end. The rating of electrolytic capacitors is easy to find because they are printed with capacitance and voltage rating. Voltage rating can be low, if it is it you should check it before using an electrolytic capacitor. Capacitors can be separated from a battery, then connected in series. You connect the positive terminal to a capacitor that is connected to a negative terminal.
- Ulaby, Fawwaz T. (1999). Fundamentals of Applied Electromagnetics (1999 ed.). Upper Saddle River, New Jersey: Prentice-Hall. p. 168. ISBN 0-13-011554-1.
- Jennifer Marcus (March 15, 2012). "Researchers develop graphene supercapacitor holding promise for portable electronics". http://newsroom.ucla.edu/portal/ucla/ucla-researchers-develop-new-graphene-230478.aspx. Retrieved 29 May 2012.
- "CAPACITORS AND DIELECTRICS". http://teacher.nsrl.rochester.edu:8080/phy122/lecture_notes/chapter27/Chapter27.html. Retrieved 31 May 2012.
Other websites [change]
|Wikimedia Commons has media related to: capacitors|
- Introduction To Capacitors Capsite 2009