Benchmark Companies Inc PO Box 473768 Aurora CO 80047 Conductors, Insulators, Semiconductors.

Benchmark Companies IncPO Box 473768Aurora CO 80047

Conductors, Insulators, Semiconductors

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Upon completion, you will: Be given information on Conductors Be given information on Insulators Be given information on Semiconductors Be presented the information needed to complete the

Exercise “ELT106 Electron Theory” Be presented the information needed to complete the

Exercise “ELT106 Conductors”

Conductors, Insulators, Semiconductors Conductors Insulators Semiconductors

Introduction

In this lesson we will discuss the atomic level difference between Insulators, conductors and semiconductors. We will also explore the uses of each of these different types of elements

Conductors

Electrons can flow in all matter. However, this flow is much easier through some materials than others. A good conductor is material through which electrons can easily flow with little energy applied.

Conductors

There are a variety of conductors on the market.

Conductors

Each size is designed for a specific purpose

ConductorsEach specific purpose may required a specific type of conductor.

ConductorsMetals such as copper, silver, gold, aluminum and iron are considered good conductors since they have many free electrons.

+29

Cu1 valence electron

+47

Ag1 valence electron

+79

Au1 valence electron

+13

Al3 valence electrons

+26

Fe2 valence electrons

ConductorsCopper is the most commonly used conductor because it is relatively inexpensive and has good conducting ability.

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+47


+79


+13


+26


ConductorsThe electrical conducting properties of various materials are determined by the number of electrons in the valence shell of the atoms

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+47


+79


+13


+26


ConductorsThe outer shell (valence shell) never contains more than 8 electrons. Generally, a conductor has only 1,2 or 3 electrons in its outer shell.

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+47


+79


+13


+26


Conductors

The electrons in these shells are held loosely and there is room for more.

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+47


+79


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+26


Conductors

There is no such thing as an ideal conductor. In an ideal conductor there would be no resistance to electron flow. This would be ideal in electronics.

Conductors

Due to physical effects of friction caused by electron movement, heat by external forces and by the structure of the conductor itself, The electron movement has some resistance.

Conductors

Conductors have very low resistance. Less than 1 Ohm for 10 ft of copper is a Typical value.

Conductors

Examples of wire sizes are:size diameter cmil Ohms/1000 feet Typ. Current

limit 22 AWG 25.35 mil 642.4 16.46 0.5-1.0 Amp 20 AWG 31.96 mil 1022 10.35 18 AWG 40.30 mil 1624 6.510 16 AWG 50.82 mil 2583 4.090 14 AWG 64.08 mil 4107 2.575 15Amp 120Volt 12 AWG 80.81 mil 6530 1.619 20Amp 240Volt 10 AWG 101.9 mil 10,380 1.018 30Amp 120/240Volt 8 AWG 128.5 mil 16,510 0.6405 40Amp 120/240Volt 6 AWG 162.0 mil 26,250 0.4028 4 AWG 204.3 mil 41,740 0.2533 2 AWG 257.6 mil 66,370 0.1593

Wire sizes are measured by a standard known as AWG (American Wire Gage).

Conductors



Wire sizes are measured by a standard known as AWG (American Wire Gage).Diameter is measured in mils. 1 mil is equal to 1/1000th of an inch.

Conductors



Wire sizes are measured by a standard known as AWG (American Wire Gage).Diameter is measured in mils. 1 mil is equal to 1/1000th of an inch.A circular mil is equal to 1mil2.

Conductors



Wire sizes are measured by a standard known as AWG (American Wire Gage).Diameter is measured in mils. 1 mil is equal to 1/1000th of an inch.A circular mil is equal to 1mil2. Typical resistance for annealed copper wire.

Conductors



Wire sizes are measured by a standard known as AWG (American Wire Gage).Diameter is measured in mils. 1 mil is equal to 1/1000th of an inch.A circular mil is equal to 1mil2. Typical resistance for annealed copper wire.Some typical current limits for various gages of wire.

Conductors

The larger the diameter of wire, the more current can be allowed to flow safely. The smaller the diameter, less current can flow safely.

AWG NUMBER 18 14 10 8 6 0Approx.

Cross-

Sectional area

AWG wire sizes

Less current More current

Conductors

The larger the diameter of wire, the less resistance in the conductor. The smaller the diameter, the more resistance in the conductor.

AWG NUMBER 18 14 10 8 6 0Approx.

Cross-

Sectional area

AWG wire sizes

more resistance less resistance

Insulators

An insulator is a material that has few, if any, free electrons and resists the flow of electrons.

Insulators

Generally, insulators have full valence shells of five to eight electrons. The electrons are held tightly, the shell is fairly full and very high voltage is needed to cause any electron flow.

Insulators

Some common insulators are air, glass, rubber, plastic, paper and porcelain.

Insulators

Insulators are used in electric circuits to keep electrons flowing along the intended path of the circuit.

Insulators

No material has been found to be a perfect insulator. Every material can be forced to permit a small flow of electrons from atom to atom if enough energy in the form of voltage is applied.

Insulators

Whenever a material that is classified as an insulator is forced to pass an electric current, the insulator is said to have been broken down or ruptured.

Semiconductors

A semiconductor is a material that has some characteristics of both conductors and insulators.

Semiconductors

Semiconductors have a valence shell which contains 4 electrons.

Semiconductors

A pure semiconductor may act as either a conductor or an insulator depending on the temperature at which operated.

Semiconductors

Operated at low temperatures, it is a fairly good insulator.

Semiconductors

Operated at high temperatures, it is a fairly good conductor.

Semiconductors

Common examples of semiconductor materials is silicon (Si) and germanium (Ge).

Semiconductors

Specially treated semiconductors are used to produce modern electronic components such as diodes, transistors and integrated circuits.

Semiconductors

These semiconductors are the brains of high tech machines, driving everything from pocket calculators to cell phones.

Summary

ConductorsAllow electrons to move freelyLess than 4 electrons in valence shellExamples Copper, Silver, Gold and Iron

Summary

InsulatorsElectrons flow is restrictedUsually a valence shell with many electrons

held tightly.Examples Glass, Rubber, Plastic, paper and

porcelain

Summary

Semiconductors Electrons flow depends on the temperature of the

material Low temperature makes semiconductor an insulator. High Temperature makes semiconductor a conductor.

Has 4 valence electrons in the outer shell. Examples of semiconductor material is silicon and

germanium

End of Lesson

Benchmark Companies Inc PO Box 473768 Aurora CO 80047 Conductors, Insulators, Semiconductors.

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