CAPACITORS

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• What is capacitor? First Capacitor (Leyden Jars)
• Structure of Capacitor
• Types and Styles
• Function of Capacitors

A capacitor (condenser) is a passive two-terminal electrical component used to store electrical energy temporarily in an electric field.

Leyden Jars(The first known capacitor)

Pieter van Musschenbroek(1700–1748)

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Structure of a Capacitor: A capacitor is composed of two conductors separated by an insulating material called a DIELECTRIC. The dielectric can be paper, plastic film, ceramic, air or a vacuum. The plates can be aluminium discs, aluminium foil or a thin film of metal applied to opposite sides of a solid dielectric.

structure ;

types and styles

• Fixed Capacitors
• Adjustable Capacitors

fixed capacıtors

• Mica capacitor
• Ceramic capacitor
• Paper capacitor
• Electrolytic capacitor
• Tantalum capacitor

MICA CAPACITORS are capacitors which use mica as the dielectric. There are two types of mica capacitors: clamped mica capacitors and silver mica capacitors. Clamped mica capacitors are now considered obsolete due to their inferior characteristics. Silver mica capacitors are used instead.

A CERAMIC CAPACITOR is a non-polarized fixed capacitor made out of two or more alternating layers of ceramic and metal in which the ceramic material acts as the dielectric and the metal acts as the electrodes. The ceramic material is a mixture of finely ground granules of paraelectric or ferroelectric materials, modified by mixed oxides that are necessary to achieve the capacitor's desired characteristics.

A PAPER CAPACITOR is made of flat thin strips of metal foil conductors that are separated by waxed paper (the dielectric material). Paper capacitors usually range in value from about 300 picofarads to about 4 microfarads.

An ELECTROLYTIC CAPACITOR is used where a large amount of capacitance is required. As the name implies, an electrolytic capacitor contains an electrolyte. This electrolyte can be in the form of a liquid (wet electrolytic capacitor). The wet electrolytic capacitor is no longer in popular use due to the care needed to prevent spilling of the electrolyte.

A TANTALUM CAPACITOR is a type of electrolytic capacitor and usually consists of a pellet of tantalum metal that acts as an anode, is covered by an insulating oxide layer which forms the dielectric and is surrounded by conductive material that acts as a cathode. Tantalum capacitors are different from other capacitors by having high capacitance per weight and volume. Tantalum capacitors have lower ESR (equivalent series resistance), higher operating temperature and lower leakage than other types of electrolytic capacitors

ADJUSTABLE CAPACITORS

• Variable capacitor
• Trimmer capacitor
• Varicap(varactor) capacitor
• Varistor capacitor

VARIABLE CAPACITORS are capacitors with variable capacity.The insulator (dielectric) between the plates is air or a thin layer of plastic, hence the name variable capacitor.

TRIMMER CAPACITORS are almost always mounted directly on the PCB, so the user does not have access to them, and set during manufacturing using a small screwdriver. Trimmer capacitors on variable capacitor is minimized.Dielectric materials; mica,ceramic, and the air..

VARACTOR DIODES or VARICAP DIODES are used as voltage-controlled capacitors.

VARISTORS are used as control or compensation elements in circuits either to provide optimal operating conditions or to protect against excessive transient voltages.

FUNCTION OF CAPACITORS IN A CIRCUIT;

• electric charge storage
• reactive power control
• prevent loss of information
• AC/DC conversion
• (electronic and electrical systems)

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• AC/DC conversion
• A Capacitor consists of two metal plates separated by a dielectric.
• The dielectric can be made of many insulating materials such as air, glass, paper, plastic etc.
• A capacitor is capable of storing electrical charge and energy.
• The larger the area of the plates or the smaller their separation the more charge the capacitor can store.

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• Capacitance is measured in Farads, which is a very large unit so micro-Farad ( uF ), nano-Farad ( nF ) and pico-Farad ( pF ) are generally used.

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• http://www.teknokoliker.com/2013/05/kondansator-cesitleri-ve-sembolleri.htm...
• http://www.capacitorguide.com/mica-capacitor/
• http://www.tpub.com/neets/book2/3f.htm
• http://www.mikroe.com/old/books/keu/02.htm
• https://en.wikipedia.org/wiki/Capacitor http://www.technologystudent.com/elec1/capac1.htm