WORKSHOP PRACTICE WEEK-3

OBJECTIVE OF LAB-2 To be familiar with the capacitor and the inductor.

THE BASICS OF CAPACITORS The basic form of a capacitor is two electrodes (metal plates) facing each other, with a gap in between. When a DC voltage (V) is applied to the two electrodes, electrons will instantly collect on one side, causing that electrode to have a negative charge, while electrons on the other electrode will be lacking, which means that it has a positive charge. This condition will remain also when the DC voltage is removed. In other words, an electric charge (Q) has now accumulated between the two electrodes.

BASIC CONSTRUCTION

ELECTROSTATIC CAPACITY A numeric value expressing how much charge a capacitor can hold is called the electrostatic capacity, or capacitance (C) for short. Dielectric constant or permittivity is the measure of a material's ability to resist an electric field Vacuum has lowest permittivity i.e electric field would be strongest in vacuum.

When a dielectric (made of a ceramic material, plastic film, etc When a dielectric (made of a ceramic material, plastic film, etc.) is inserted between the two electrodes, the dielectric polarization effect results in a higher charge.

DIELECTRIC POLARIZATION Dielectric polarization is the term given to describe the behavior of a material when an external electric field is applied on it. A simple picture can be made using a capacitor as an example. The figure below shows an example of a dielectric material in between two conducting parallel plates

DIELECTRIC POLARIZATION

Types of Capacitors Fixed (whose capacitance cannot be changed) Variable (Capacitance can be changed)

TYPES OF (Fixed) CAPACITORS: There are a very, very large variety of different types of capacitor available in the market place and each one has its own set of characteristics and applications, from very small delicate trimming capacitors up to large power metal-can type capacitors used in high voltage power correction and smoothing circuits. But basically there are two types of capacitors: 1- Electrolytic and 2- Non – electrolytic capacitors. The non- Electrolytic capacitors use Paper, Mica, Ceramic, Mylar, Glass, Porcelain, Polycarbonate, and Wax as Insulator.

ELECTROLYTIC CAPACITOR POLARITY MUST BE OBSERVED NON ELECTROLYTIC CAPACITOR

Non Electrolytic Capacitors Film Capacitor Film Capacitors are the most commonly available of all types of capacitors, consisting of a relatively large family of capacitors with the difference being in their dielectric properties. These include polyester (Mylar), polystyrene, polypropylene, polycarbonate, metalised paper, Teflon etc. Film type capacitors are available in capacitance ranges from as small as 5pF to as large as 100uF depending upon the actual type of capacitor and its voltage rating. Film Capacitors which use polystyrene, polycarbonate or Teflon as their dielectrics are sometimes called “Plastic capacitors”.

A ceramic capacitor is a fixed- value capacitor in which ceramic material acts as the dielectric. 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. Disc and Multilayer Ceramic Capacitors MLCC.

CAPACITOR NUMBER CODING

Inductor Types Fixed or adjustable. Core Material Used.

INDUCTOR NUMBER CODING

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