ACTIVE LEARNING PROCESS

Prepared By :NISARG AMIN 14BEEEG012KUNJ SHAH 14BEEEG010DEEP PANDYA 14BEEEF011Guided By :

SHEETAL M PUJARAHARDIK AGARWAL

BRANCH: FY ELECTRICAL -1TOPIC: CAPACITOR

CapacitorsA basic capacitor has two parallel

conducting plates separated by an insulating material.

The conducting plates can be thin films, foils, conductive electrolyte, etc.

A dielectric i.e. insulating material can be glass, ceramic, plastic film, air, vacuum, paper, mica, etc.

The dielectric increases the capacitor's charge capacity.

A capacitor stores an electrical charge between the two plates.The unit of capacitance is Farads (F).Capacitance values are normally smaller, such as µF, nF or pF.Capacitors are widely used as parts of electrical circuits in many common electrical devices.Capacitors doesn’t dissipate energy in any form.

• Basic capacitor construction:-Dielectric material

Plate 1

Plate 2The dielectric material is an insulator therefore no current flows through the capacitor.

• Storing a charge between the plates:-

Electrons on the left plate are attracted toward the positive terminal of the voltage source.

This leaves an excess of positivelycharged holes.

The electrons are pushed towardsright plate.

Excess electrons leave a negative charge.

+ -

+_

+ _

Types Of CapacitorsCapacitors are classified into two

groups:-

1. Polarized – Electrolytic capacitors

2. Non-Polarized – Ceramic, Silver Mica, Polyester, Polystyrene, Teflon capacitors.

• Electrolytic Capacitors:-An electrolytic capacitor is

a capacitor that uses an electrolyte as one of its plates to achieve a larger capacitance per unit volume than other types.

The large capacitance of electrolytic capacitors makes them particularly suitable for passing or bypassing low-frequency signals and storing large amounts of energy

They are widely used in power supplies and in interconnecting stages of amplifiers at audio frequencies.

An electrolytic capacitor will generally have higher leakage current than a dry capacitor, and may have significant limitations in its operating temperature range and the stability and accuracy of its capacitance value.

Two types of electrolytic capacitors are in common use: aluminum and tantalum.

• Ceramic capacitor:-

Ceramic material acts as the dielectric in a ceramic capacitor .

It is constructed of two or more alternating layers of ceramic and a metal layer acting as the electrodes. The composition of the ceramic material defines the electrical behavior and therefore applications.

• Silver mica capacitor:-Silver mica capacitors are high precision,

stable and reliable capacitors.

They are available in small values, and are mostly used at high frequencies and in cases where low losses and low capacitor change over the time is desired.

There are two types of silver mica capacitors:

1. Clamped Mica capacitors

2. Silvered mica capacitors

• Polyester Capacitor:-

Polyester film acts as dielectric

in this type of capacitor.

Polyester capacitors offer

very less tolerance.

There are two types of polyester capacitor:

1. Metalized Film Capacitor

2. Foil Capacitor

Applications• Energy storage:-

A capacitor can store electric energy when disconnected from its charging circuit, so it can be used like a temporary battery, or like other types of rechargeable energy storage systems.

Capacitors are commonly used in electronic devices to maintain power supply while batteries are being changed.

• Pulsed power and weapons:-

Groups of large, specially constructed, low-inductance high-voltage capacitors are used to supply huge pulses of current for many pulsed power applications.

Large capacitor banks are used as energy sources for the exploding-bridgewiredetonators or slapper detonators in nuclear weapons and other specialty weapons.

• Power factor correction:-

In electric power distribution, capacitors are used for power factor correction.

Such capacitors often come as three capacitors connected as a three phase load.

Usually, the values of these capacitors are given not in farads but rather as a reactive power in volt-amperes reactive.

• Capacitive Coupling:-

Polyester film capacitors are frequently used as coupling capacitors.

As capacitors pass AC but block DC signals, they are often used to separate the AC and DC components of a signal. This method is known as AC coupling or "capacitive coupling".

• Tank Circuits:-

Variable Capacitors are used in tank circuits to control the frequency of the material.

Frequency is given by:-

• Filters:-

Capacitors are the main elements of filters.

There are several types of filters that are used in electronic circuits such as Low Pass Filter(LPF),High Pass Filter(HPF),Band Pass Filter(BPF),etc.

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