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Introduction of simple conduction, including the basic ideas and models of conductor.

Our initial studies will more or less be a review of topics in electricity that you may have seen before in physics. However,if experience is any guide, there is no great harm in going back over this material, for it seems that for many students, thewhole concept of just how electricity actually works is just a little hazy. Considering that you hope to be called anelectrical engineer one of these days, this might even be a good thing to know!

Most of the "laws" of how electricity behaves are really just mathematical representations of a number of empiricalobservations, based on some assumptions and guesses which were made in attempt to bring the "laws" into a coherent whole.Early investigators (Faraday, Gauss, Coulomb, Henry etc....all those guys) determined certain things about this strange"invisible" thing called electricity. In fact, the electron itself was only discovered a little over 100 years ago. Even beforethe electron itself was observed, people knew that there were two kinds of electric charge, which were called positive and negative . Like charges exhibit a repulsive force between them and opposite chargesattract one another. This force is proportional to the product of the absolute value of positive and negative charge, andvaries inversely with the square of the distance between them. Different charge carriers have different mass, some are verylight, and others are significantly heavier. Electrical charges can experience forces, and can move about. Since force timesdistance equals work, a whole system of energy ( potential as well as kinetic ) and energy loss had to be described. This has lead to our currentsystem of electrostatics and electrodynamics, which we will not review now but bring up along the way as things are needed.

Just to make sure everyone is on the same footing however, let's define a few quantities now, and then we will see how theyinteract with one another as we go along.

The total charge in some region is defined by the symbol Q and it has units of Coulombs. The fundamental unit of charge (that of an electron or a proton)is symbolized either by a little q or by e . Since we'll use e for other things, in this course we will try to stick with q . The charge of an electron , q , has a value of 1.6 -19 Coulombs.

Since charge can be distributed throughout a region with varyingconcentrations, we will also talk about the charge density , ρ ν , which has units of Coulombs cm 3 . (In this book, we will use a modified MKS system of units. In keeping with most workers in the solid-state devicefield, volume will usually be expressed as a cubic centimeter, rather than a cubic meter - a cubic meter of silicon is just fartoo much!) In most cases, the charge density is not uniform but is a function of where we are in space. Thus, when we have ρ ν distributed throughout some volume, V

Q ν V ρ ν
describes the total charge in that volume.

Questions & Answers

difference between microeconomics and macroeconomic
Ugyen Reply
what is monopoli power
Adzaho Reply
the situation that prevails when economic forces balance so that economic variables neither increase nor decrease
Bombey
what is equilibrium
Kabir
what are the important of economic to accounting students with references
salihu Reply
Economics is important because it helps people understand how a variety of factors work with and against each other to control how resources such as labor and capital get used, and how inflation, supply, demand, interest rates and other factors determine how much you pay for goods and services.
Muhammad
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Azeem Reply
contribution of Adam smith in economics
abel Reply
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AS
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Umarou
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Amir
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Effah Reply
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Isaac Reply
Is the degree to the degree of responsiveness of a change in quantity supplied of goods to a change in price
Afran
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Humaira
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scor
And what are the resources in land
scor
what is production
Humaira
the proces of using the services of labor and equipmnt together with other in puts to make goods and services availble
Bombey
Okay what is land mobile and land unmobile
scor
Discuss the short-term and long-term balance positions of the firm in the monopoly market?
Rabindranath Reply
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Soumya
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Mitiku
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Mitiku
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Soumya
through hard study and performing well than expected from you
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Mitiku
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Soumya
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Rabindranath
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OLANIYI
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Liaqat
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Anteyi Reply
A firm is a business entity which engages in the production of goods and aimed at making profit.
Avuwada
What is autarky in Economics.
Avuwada
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Tia Reply
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Rev Reply
what is choice
Tia
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Alfred Reply
1
Naziru
what is the difference between short run and long run?
Ukpen Reply
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Anna
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Ukpen
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Ukpen
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Docky
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Docky
Okay and I was being serous
Anna
The short run is a period of time in which the quantity of at least one inputs is fixed...
Anna
that is the answer that I found online and in my text book
Anna
Elacisity
salihu
Meaning of economics
Suraj Reply
It will creates rooms for an effective demands.
Chinedum Reply
different between production and supply
babsnof
Hii
Suraj
hlo
eshita
What is the economic?
Suraj
Economics is a science which study human behavior as a relationship between ends and scarce means which has an alternative use.
Mr
what is supply
babsnof
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Source:  OpenStax, Introduction to physical electronics. OpenStax CNX. Sep 17, 2007 Download for free at http://cnx.org/content/col10114/1.4
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