here are many kind of capacitors

7/31/2019 Here Are Many Kind of Capacitors

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here are many kind of capacitors, they all do same thing: store electric charge. Simplest capacitor

is two conductors separated by an insulating material called the dielectric. The dielectric can bepaper, plastic, film, mica, glass, ceramic, air or vacuum.

When a voltage is applied across the two plates of a capacitor, a concentrated field flux is created

between them, allowing a significant difference of free electrons (a charge) to develop betweenthe two plates.

When the voltage across a capacitor is increased, it draws current from the rest of the circuit,

acting as a power load. Conversely, when the voltage across a capacitor is decreased, the

capacitor supplies current to the rest of the circuit, acting as a power source.

The ability of a capacitor to store energy in the form of an electric field (and consequently is

called capacitance. It is measured in the unit of the Farad (F).

1 Farad = 1 F

1 Microfarad = 1 uF1 Nanofarad = 1 n

i Picofarad = 1 pF

Types of Capacitors

Following are some of the important types of capacitors used commonly in practical circuits.

1. Ceramic Capacitor

This is one of the most commonly and widely used capacitor in electronic components. Aceramic capacitor is a capacitor constructed of alternating layers of metal and ceramic,with the ceramic material acting as the dielectric. They are well suited for use in high

frequency applications ranging up to couple of thousands of MHz. These capacitors are



available from fraction of a pF to 1uF (1000000 pF)

2. Electrolytic Capacitor

Aluminum electrodes are used and they are separated by using a thin oxidation

membrane. This is a most common type, polarized capacitor. Cheap, readily available,good for storage of charge. Not very accurate, leakage, drifting, not suitable for use in HF

(High Frequency) circuits, available in very small to very large values in uF. The most

important characteristic of electrolytic capacitors is that they have polarity. They have a

positive and a negative electrode. This means that it is very important that the terminalsare connected to the right poles.

3. Tantalum Capacitors

These capacitors are made of Tantalum Pentoxide. Superior to electrolytic capacitors,

excellent temperature and frequency characteristics. Like electrolytic, tantalum capacitors

are polarized so watch the '+' and '-' indicators. Tantalum capacitors are a little bit more

expensive than aluminum electrolytic capacitors. These capacitors are very stable withtemperature and frequency changes. Therefore, tantalum capacitors are used for circuits

which demand high stability in the capacitance values, e.g. analog signal systems, and

because the current-spike noise that occurs with aluminum electrolytic capacitors does



not occur here.

4. Metalized Polyester Film

No polarity, dielectric made of Polyester.Good quality, low drift, temperature stable.

Because the electrodes are thin they can be made really small. Typically used in audioand communication equipments.



5. Trimmer Capacitors

These use mostly plastic as a dielectric. The capacitance of this type of capacitors can beadjusted using a screw driver. These capacitors are adjusted at the time of manufacture of



the electronic equipment.

6. Variable Capacitors

Variable capacitors are typically air-cored or sometimes uses plastic as a dielectric.

Typically connected to knobs to let the user tune the capacitance, so most of them aredesigned to connect to a rotating knob. These capacitors are typically used in radios.

7. Polyester Film Capacitors

This capacitor uses a thin polyester film as a dielectric. Not as high a tolerance as

polypropylene, but cheap and handy, temperature stable, widely used.

8. Polypropylene Capacitors



Mainly used when a higher tolerance is needed than polyester caps can offer. In these

capacitors polypropylene film is the dielectric.

9. Polystyrene Capacitors

In this Polystyrene is used as a dielectric. Constructed like a coil inside so not suitable for

high frequency applications. Well used in filter circuits or timing applications using a

couple hundred KHz or less.

10. Multilayer Ceramic Capacitors

Dielectric is made up of many layers. Small in size, very good temperature stability,

excellent frequency stable characteristics. Used in applications to filter or bypass the high

frequency to ground.

11. Silver-Mica Capacitors

Mica is used as a dielectric. Used in resonance circuits, frequency filters, and military RFapplications. Highly stable, good temperature coefficient, excellent for endurance

because of their frequency characteristics, no large values, high voltage types available,

are relatively expensive.

12. Supercapacitor



An Electric double-layer capacitor, also known as supercapacitor, supercondenser,

pseudocapacitor, electrochemical double layer capacitor (EDLC), or ultracapacitor, is anelectrochemical capacitor that has an unusually high energy density when compared to

common capacitors, typically on the order of thousands of times greater than a high

capacity electrolytic capacitor. Whereas a regular capacitor consists of conductive foils

and a dry separator, the supercapacitor crosses into battery technology by using specialelectrodes and some electrolyte. There are three types of electrode materials suitable for

the supercapacitor. They are: high surface area activated carbons, metal oxide and

conducting polymers. The high surface electrode material, also called Double LayerCapacitor (DLC), is least costly to manufacture and is the most common. It stores the

energy in the double layer formed near the carbon electrode surface. To know more about

supercapacitor and ultracapacitor visit below links.

Supercapacitor overview

Details on supercapacitor and how it works

Manufacturer of supercapacitor

Suggested links

http://en.wikipedia.org/wiki/Electric_double-layer_capacitor


http://www.supercapacitors.org/


http://www.maxwell.com/ultracapacitors/index.asp







Types of capacitors and interesting animation of capaitor

http://www.splung.com/content/sid/3/page/capacitors



here are many kind of capacitors

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