1. Essentials of Electronics Second Edition Frank D. Petruzella Glencoe/McGraw-Hill

2. CHAPTER 3 CONDUCTORS, SEMICONDUCTORS AND INSULATORS Most materials belong to one of three broad groups: conductors, insulators, and semiconductors. The borderlines are not clear, though, and many substances cannot easily be put into one group or the other.

3. CHAPTER 3 CONDUCTORS, SEMICONDUCTORS AND INSULATORS In this chapter you will learn about the atomic structure of each group.

4. OBJECTIVES 1.Describe the structure of an atom. 2.Recognize, at the atomic level, the characteristics of conductors, semiconductors, and insulators. 3.Explain the ionization process. 4.Recognize common conductor, semiconductor, and insulating materials. 5.Define electricity.

5. Key Definitions Electron Theory of Matter: –All matter, solid, liquid, gas, is comprised of molecules, which in turn are comprised of atoms, which are again comprised of protons, neutrons and electrons. Define Molecule: –The smallest part of matter which can exist by itself, still retains properties of original substance.

6. Structure of an atom Neutron Proton Electron Shell or energy level: how electrons are arranged around the nucleus, An atom is the smallest particle of matter, contains E,P,N’s.

7. 13 P 14 N Bohr model of the aluminum atom 13=13 Protons = Electrons Net charge is neutral or zero

8. Placement of electrons in a copper atom +29 Complete with 2 Complete with 8 Complete with 16 Incomplete with 1

9. Electricity-the flow of free electrons Bound electron Free electron Valance electron Negative source Positive source

10. Atomic structure of conductors, insulators, and semiconductors Insulator - full valence shell Conductor - 1 to 3 valence electrons Semiconductor - 4 valence electrons

11. Common Conductors and Insulators ConductorsInsulators

12. Continuity Tester What is Continuity? –Determines if a circuit is complete. How is measured? –Low resistance = continuity –High resistance = no continuity. How might you be able to build a basic continuity tester? –Lamp, battery, test leads… Continuity Tester Lab

13. Continuity test (closed circuit) Copper wire conductor Lamp “on”

14. Lamp “off” Insulator Continuity test (open circuit)

15. Light “on” indicates continuous path Tester internal circuit Continuity Tester

16. Electronic Devices Electron tube Transistor Integrated circuit What is Solid state? What does it mean to be electronic? Uses electron tubes or semiconductors. Uses semiconductors.