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Tutorial: Mechanic - electrician Topic: Technical training II. class Semiconductor devices 1 Prepared by: Melichak Lubomr Projekt Anglicky v odbornch pedmtech, CZ.1.07/1.3.09/04.0002 je spolufinancovn Evropskm socilnm fondem a sttnm rozpotem esk republiky.

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SEMICONDUCTORS A semiconductor is a solid material, whose electrical conductivity depends on external or internal conditions, and one can easily change these conditions influence. A change in the external conditions meaning the delivery of some type of energy usually heat, electricity or light, a change in the internal conditions by introducing a dash of a different element in the semiconductor.

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TYPES OF SEMICONDUCTORS Among the semiconductor elements are: -silicon -germanium -selenium -compounds gallium arsenide GaAs -Lead sulphide PbS Most semiconductors are crystalline substances, but there are also amorphous semiconductors (some glass)

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SEMICONDUCTOR DIVISION By structure - organic, inorganic According to the major charge carriers - n- semiconductors, p-semiconductors According to the origin of charge carriers proper semiconductors, step-semiconductors According to the nature of the jump over mechanisms between the bands -direct semiconductors, indirect semiconductors According to the statistical distribution of the carriers- undegenerate semiconductor, degenerate semiconductor

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N-type Semiconductor If we add to pure silicon with four valence electrons an element with five valence electrons (phosphorus, arsenic or antimony), there will be an N-type semiconductor. P-type Semiconductor If we endow a silicon element with three valence electrons (boron, aluminum, gallium or indium)a P-type semiconductor is created. Using semiconductors additives Semiconductor additives are used in semiconductor devices, primarily in the semiconductor diode and transistor, where they play a crucial role in the P-N junction.

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Semiconductor device is an electronic device utilized for its functional specific properties as a semiconductor such as germanium (Ge) and silicon (Si) Semiconductor devices are: Diodes, bipolar and unipolar transistors, thyristors, diacs and triacs.

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BASIC SCHEMATIC SYMBOLS Electrotechnical schematic symbol for diodes Electrotechnical schematic symbol for an NPN transistor Electrotechnical schematic symbol for a PNP transistor

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1. What is a semiconductor? 2. Name the types of semiconductors. 3. How are semiconductors divided? 4. What is a semiconductor device?

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1. Draw the schematic symbol for diodes 2. Draw the schematic symbol for an NPN transistor 3. Draw the schematic symbol for a PNP transistor

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Vclav MalinaPoznvme elektroniku I. Adrian Schommers Elektronika tajemstv zbaven. ISBN 3-92608-32-5