Capacitor

Capacitor is an electrical device that can store electrical energy. Capacitance is the concept of energy storage in an electric field and is restricted to the area, shape, and
spacing of the capacitor plates and the property of the material separating them. Capacitance measured in Farad. Capacitor that we usually used in micro, pico, or nano Farad.
Capacitors are used to filter, couple, tune, block dc, pass ac, bypass, shift phase, compensate, feed through, isolate, store energy, suppress noise, and start motors. They must also be small, lightweight, reliable, and withstand adverse conditions.

Breakdown voltage
Capacitor have parameter that called breakdown voltage. Break down voltage is the maximum voltage that can apply to a capacitor. When we applied voltage larger than break down voltage, capacitor will damaged and some times can be exploded.

Types of Capacitors
Ceramic Capacitors
Ceramic capacitors are used most often for bypass and coupling applications. Ceramic capacitor have capacitance range from 1.0pF to 4.7uF. Ceramic capacitors have no polarity.
Ceramic capacitors should not be used for analog circuits, because they can distort the signal.

Film Capacitors
Film capacitors consist of alternate layers of metal foil and one or more layers of a flexible plastic insulating material (dielectric) in ribbon form rolled and encapsulated.

Mica Capacitors
Mica capacitors have small capacitance values and are usually used in high-frequency circuits. They are constructed as alternate layers of metal foil and mica insulation, which are stacked and encapsulated, or are silvered mica, where a silver electrode is screened on the mica insulators.

Paper-Foil-Filled Capacitors
Paper-foil-filled capacitors are often used as motor capacitors and are rated at 60 Hz. They are made of alternate layers of aluminum and paper saturated with oil that are rolled together. The assembly is mounted in an oil filled, hermetically sealed metal case.

Electrolytic Capacitors
Electrolytic capacitors provide high capacitance in a tolerable size; however, they do have drawbacks. Low temperatures reduce performance, while high temperatures dry them out. The electrolytes themselves can leak and corrode the equipment. Repeated surges above the rated working voltage, excessive ripple currents, and high operating temperature reduce performance and shorten capacitor life. Electrolytic capacitors are manufactured by an electro chemical formation of an oxide film on a metal surface.
The metal on which the oxide film is formed serves as the anode or positive terminal of the capacitor; the oxide film is the dielectric, and the cathode or negative terminal is either a conducting liquid or a gel.