Kuliah BBL-2 Mf

8/13/2019 Kuliah BBL-2 Mf

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Perilaku

Bahan-Bahan ListrikKuliah

Bahan-Bahan Listrik

Elektro UNDIP


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2003 Brooks/Cole, a division of Thomson Learning, Inc. Thomson Learning

is a trademark used herein under license.


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Illustration

(a) Charge carriers, such aselectrons, are deflected byatoms or defects and take anirregular path through aconductor. The average rateat which the carriers move isthe drift velocity v.

(b) Valence electrons in themetallic bond move easily.(c) Covalent bonds must bebroken in semiconductorsand insulators for anelectron to be able to move.

(d) Entire ions must diffuseto carry charge in manyionically bonded materials.

2003Brooks/Cole,adivisionofThomson

Learning,Inc.ThomsonLearningisatrademarkused

herein

underlicense.


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Mean free path

The average distance

that electrons can

move without being

scattered by other

atoms.


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.time

charge

I

.sec

coulomb1ampere1

A

IJ~

Current density

Current


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Current density

The current flowing

through per unit cross-

sectional area.


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AR

A

1R

Electrical resistance

where is the electrical conductivity

is the electrical resistivity

R

A


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VI

R

JV

E

V

I JAV

V

R

V A

1R


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Electric fieldThe voltage gradient or

volts per unit length.


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V

dx

dV

dx

dVE

Edx

dVV

E

J~

Electric field


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v E

v = E

Drift velocity

where is the mobility


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Drift velocity & Mobility

Drift velocity - The average rate

at which electrons or other

charge carriers move through a

material under the influence of anelectric or magnetic field.

Mobility - The ease with which a

charge carrier moves through a

material.


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Several Terms

Current density - The current flowing throughper unit cross-sectional area.

Electric field - The voltage gradient or volts per

unit length.

Drift velocity - The average rate at which

electrons or other charge carriers move througha material under the influence of an electric or

magnetic field.

Mobility - The ease with which a charge carrier

moves through a material.

Dielectric constant - The ratio of the permittivityof a material to the permittivity of a vacuum,

thus describing the relative ability of a material

to polarize and store a charge; the same as

relative permittivity.

IJA

Edx

dVV

v E

ro


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Several terms

Valence band - The energy levels filled byelectrons in their lowest energy states.

Conduction band - The unfilled energy levels

into which electrons can be excited to

provide conductivity.

Energy gap (Bandgap) - The energy between

the top of the valence band and the bottom of

the conduction band that a charge carriermust obtain before it can transfer a charge.


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Kuliah BBL-2 Mf