Capacitor

Modern capacitors, by a cm ruler

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.

The type of capacitor used depends on the application. Capacitors come in many sizes. They can be as small as an ant or as large as a dustbin.

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.

• 

  Capacitors dipped in plastic

• 

  Capacitors as a box

Other websites

• Introduction To Capacitors Capsite 2009