Conductors, insulators, and electron flow

Chapter 1.2 Conductors, insulators, and electron flow

Lessons In Electric Circuits Volume I – DC Book
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Summary of Contents

Lessons In Electric Circuits Volume I – DC Book

  • 8CHAPTER 1. BASIC CONCEPTS OF ELECTRICITY1.2Conductors, insulators, and electron flowThe electrons of different types of atoms have different degrees of freedom to move around.With some types of materials, such as metals, the outermost electrons in the atoms are soloosely bound that they chaotically move in the space between the atoms of that material bynothing more than the influence of room-temperature heat energy. Because these virtually un-bound electrons are free to leave their respective atoms and float around in the space betweenadjacent atoms, they are often called free electrons.In other types of materials such as glass, the atoms’ electrons have very little freedom tomove around. While external forces such as physical rubbing can force some of these electronsto leave their respective atoms and transfer to the atoms of another material, they do not movebetween atoms within that material very easily.This relative mobility of electrons within a material is known as electric conductivity. Con-ductivity is determined by the types of atoms in a material (the number of protons in eachatom’s nucleus, determining its chemical identity) and how the atoms are linked together withone another. Materials with high electron mobility (many free electrons) are called conductors,while materials with low electron mobility (few or no free electrons) are called insulators.Here are a few common examples of conductors and insulators:• Conductors:• silver• copper• gold• aluminum• iron• steel• brass• bronze• mercury• graphite• dirty water• concrete• Insulators:• glass