Electronics for Electricians 7E Unit 01.pptx

ELECTRONICS for ELECTRICIANS Stephen L. Herman Seventh Edition Unit 1 Semiconductors and Resistors Copyright © 2017 Cengage Learning ELECTRONICS for ELECTRICIANS Stephen L. Herman Seventh Edition Objectives • After studying this unit the student should be able to: – Discuss the differences am...

ELECTRONICS for ELECTRICIANS Stephen L. Herman Seventh Edition Unit 1 Semiconductors and Resistors Copyright © 2017 Cengage Learning ELECTRONICS for ELECTRICIANS Stephen L. Herman Seventh Edition Objectives • After studying this unit the student should be able to: – Discuss the differences among the atomic structure of conductors, insulators, and semiconductors – Give an explanation of how P- and N-type materials are made – Describe a lattice structure Copyright © 2017 Cengage Learning ELECTRONICS for ELECTRICIANS Stephen L. Herman Seventh Edition Objectives – Discuss the conduction of electric current through semiconductor materials Copyright © 2017 Cengage Learning ELECTRONICS for ELECTRICIANS Stephen L. Herman Seventh Edition Semiconductor Material • Conductors – Materials that conduct electricity easily – Contain few valence electrons (1, 2, or 3) • Semiconductors – Contain four valence electrons – Most common semiconductor materials are Germanium and Silicon Copyright © 2017 Cengage Learning ELECTRONICS for ELECTRICIANS Stephen L. Herman Seventh Edition Figure 1-4 Semiconductor atoms join together to form a covalent bond. Copyright © 2017 Cengage Learning ELECTRONICS for ELECTRICIANS Stephen L. Herman Seventh Edition Semiconductor Material (cont’d.) • Doping – Process used to add impurities to an intrinsic semiconductor material • N-type materials – Contain impurities with five valence electrons • P-type materials – Contain impurities with three valence electrons Copyright © 2017 Cengage Learning ELECTRONICS for ELECTRICIANS Stephen L. Herman Seventh Edition Semiconductor Material (cont’d.) Figure 1-7. Bricks move to the left and holes appear to move to the right. Copyright © 2017 Cengage Learning ELECTRONICS for ELECTRICIANS Stephen L. Herman Seventh Edition Figure 1-8 Electrons drift across the junction into the P region and holes drift across the junction into the N region. Copyright © 2017 Cengage Learning ELECTRONICS for ELECTRICIANS Stephen L. Herman Seventh Edition Semiconductor Material (cont’d.) gure 1-9 Measuring temperature by measuring the voltage drop across a pn junct Copyright © 2017 Cengage Learning ELECTRONICS for ELECTRICIANS Stephen L. Herman Seventh Edition Electrical Ratings of Semiconductor Devices • Voltage rating – Amount of voltage a component can withstand in the reverse direction without breaking down • Peak value in an AC circuit – Determined by multiplying the rms value by 1.414 • Current rating – Maximum amount of current the device can control Copyright © 2017 Cengage Learning ELECTRONICS for ELECTRICIANS Stephen L. Herman Seventh Edition Electrical Ratings of Semiconductor Devices (cont’d.) Figure 1-10 PN Junction Figure 1-11 Transistor Copyright © 2017 Cengage Learning ELECTRONICS for ELECTRICIANS Stephen L. Herman Seventh Edition Resistors Figure 1-12 Resistor used to limit the flow of current Figure 1-13 Resistors used as a voltage divider Copyright © 2017 Cengage Learning ELECTRONICS for ELECTRICIANS Stephen L. Herman Seventh Edition Resistors (cont’d.) • Fixed resistors – Have only one ohmic value, which cannot be changed • Carbon resistors – Popular for most applications – Will change their value with age or if overheated Copyright © 2017 Cengage Learning ELECTRONICS for ELECTRICIANS Stephen L. Herman Seventh Edition Resistors (cont’d.) • Metal film resistors – Tolerance is better than carbon resistors • Carbon film resistors – Rapidly replacing composition carbon resistors • Wire wound resistors – Operate at higher temperatures than any other type of resistor Copyright © 2017 Cengage Learning ELECTRONICS for ELECTRICIANS Stephen L. Herman Seventh Edition Figure 1-20 Resistor color code chart Copyright © 2017 Cengage Learning ELECTRONICS for ELECTRICIANS Stephen L. Herman Seventh Edition Resistors (cont’d.) • Gold as a multiplier band – Divide the first two numbers by 10 • Silver as a multiplier band – Divide the first two numbers by 100 Copyright © 2017 Cengage Learning ELECTRONICS for ELECTRICIANS Stephen L. Herman Seventh Edition Resistors (cont’d.) • Fixed resistors – Generally produced in standard values • Variable resistor – Values can be changed or varied over a range – Known by several common names: pot (from potentiometer), rheostat Copyright © 2017 Cengage Learning ELECTRONICS for ELECTRICIANS Stephen L. Herman Seventh Edition Resistors (cont’d.) Figure 1-26 Schematic symbols used to represent resistors Copyright © 2017 Cengage Learning