Transcript CHAPTER 1 SAFETY

Essentials of
Electronics
Second Edition
Frank D. Petruzella
Glencoe/McGraw-Hill
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.
CHAPTER 3
CONDUCTORS,
SEMICONDUCTORS AND
INSULATORS
In this chapter you will learn
about the atomic structure of
each group.
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.
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.
Structure of an atom
Shell or energy level: how
electrons are arranged around
the nucleus,
An atom is the
smallest particle of
matter, contains
E,P,N’s.
Proton
Neutron
Electron
Bohr model of the aluminum atom
13 P
14 N
Protons = Electrons
13=13
Net charge is neutral or zero
Placement of electrons in a copper atom
Complete with 2
Complete with 8
+29
Complete with 16
Incomplete with 1
Electricity-the flow of free electrons
Valance electron
Positive source
Negative source
Bound electron
Free electron
Atomic structure of conductors,
insulators, and semiconductors
Conductor - 1 to 3
valence electrons
Insulator - full
valence shell
Semiconductor - 4
valence electrons
Common Conductors and
Insulators
Conductors
Insulators
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
Continuity test
(closed circuit)
Lamp “on”
Copper wire
conductor
Continuity test
(open circuit)
Lamp “off”
Insulator
Continuity Tester
Light “on” indicates
continuous path
Tester internal
circuit
Electronic Devices
What is Solid state?
Uses electron tubes or semiconductors.
What does it mean to be electronic?
Uses semiconductors.
Electron tube
Integrated
circuit
Transistor