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Showing posts with the label Energy bands

Semiconductor Theory

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Semiconductors     Definition : The materials, whose electrical conductivity lies between those of conductors and insulators and have negative temperature coefficient of resistance, are known as semiconductors.   Semiconductor Materials : The few examples of semiconductor materials are as under : 1.Carbon (C) 2. Silicon (Si) 3.Germanium (Ge) 4. Selenium (Se) 5.Gallium Arsenide (GaAs) 6.Cadmium Sulphide (CdS). The commonly used semiconductor materials are Germanium and Silicon. These are tetravalent elements i.e. materials having  four valency.   Atomic Structures of Germanium and Silicon : (i) Atomic structure of Germanium and Silicon atoms :  Fig. 1.3 (b) shows the atomic structure of a Germanium atom  in which first, second, third and fourth orbits have 2, 8, 18 and  4 electrons respectively, with the result that the atomic  number for Germanium is 32. Fig. 1.3 (a) shows the atomic structure of a Silicon atom in  which first, second and th

Electric Field

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Introduction :-  If I gave a charge ( either positive or negative) to a particular particle and kept it in a room and what we observed that the charge is moving in a particular direction without being in any contact with anyone or without applying any kind of force. Despite of not applying any kind of force or a contact (by human or by other) to that charge it is moving in a particular direction. But If I took that same charge to a different place or in a different room what we observed? that charge is not moving at all like it was moving in other room instead it is static (not moving).  In some place the charge is moving very rapidly and at some it is very slower; At some places it is moving from left to right at some it  is moving from right to left. But we can't see anything. So what is that force which is driving or moving a charge or applying a force to that charge? What is that unseen thing which is applying force on the charge ? What is that thing in presence

Electric Charge

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Electrostatics is the branch of science dealing with the static electricity i.e. electricity at rest The knowledge of various laws which governs the behaviour of static electricity is essential. It is essential in the design and applications of insulation(particularly for high voltages). In the study of causes of lightning and protection against it and in the design and operation of transmission lines. Therefore, in this blog we shall briefly discuss some of the fundamental laws of electrostatics. Electric charge possess two different forms first when it is static second when it is moving. Electric charge exhibits two different properties in two different forms when it is stable state and when it is moving. When it is moving it shows properties like Electric current, Magnetic effect,Heating effect, Electromagnetic Induction and so on. Definitions: Electrostatics: Electrostatics is the branch of electricity in which properties of static (non-moving) electri