ELEMENTARY ELECTRICITY  Part 1 (of 2)
.-© 1999  -  2011  Questions or Comments about  this site  webmaster
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.Intro

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To Part 2 of 2-->
TOC
LINKS:
---INTRODUCTION ---Drop Cord Story ---Resistor Page
---In the Beginning --- ---Inductor Page
---E R I  VOLTs --- ---Capacitor Page
---E R I  OHMs
---E R I  AMPs
pop ups
---What is D.C., A. C. ---Water Modepop up ---555 Timer  pop up
--- ---Fun with Resistors  pop up ---Reading Schematics pop up
--- ---Resistor Color Code  pop up ---Wave Action  pop up
--- --- ---Parts etc. pop up
..
Introduction: Learning---Skip-

Yea Yea, I know what you're thinking: Introduction, I'm an adult, I don't have to wear a seat bel..., er... I mean, I don't read Introductions!

If you will read all of the Introduction, I promise not to ask you any questions, and we'll have Ice Cream later...

Quote of the Day:
"Since, you're so good at Math and Science you should go into Engineering."

Bogus!  BS!  . . .

Engineering is Invention, Innovation, Original Thinking, Hands-on, Doing; it has little to do with how well you do "long division," or being "good at science,." whatever the Hell that means. 

This myth is propagated by those people who wouldn't know a real Engineer from a potted plant: mostly high school guidance counselors...

Most EEs that I know only use math to figure their pay raises; which isn't that often. 

Electrical Engineering, as taught at most Universities, is nothing more than a labored Math Course. The simple reason for this travesty is that those who instruct this stuff, for the most part, have never worked 'in anger' as an EE; beyond maybe a couple of summers as a co-op. Which either bored Hell out of them (so they went into sales), or more often, scared them into graduate school

When I would ask my senior ECE students a relevant technical question, the first thing they would do was to frantically try and remember the appropriate formula, which most couldn't; much less have any understanding of the concepts

Sad to say: many Tech Schools better prepare their students for the real world of Electrical Engineering than far too many Engineering Schools. --If you find that hard to believe, just ask engineering HR (ugh, sorry) people.

For more embittered ranting & ravings see: University Education

 

"To Teach" is a somewhat meaningless term. 

I cannot teach anyone anything; I can only HELP them to Learn something--maybe.   I can try to be an Enabler.

To really Learn requires full participation by the Learner: "One can lead a horse to water, but can't make him do the backstroke."

Also, and more importantly, Learning is NOT a linear process. No one learns in a straight line, logically or sequentially. I have only met one person who claimed to learn in a linear fashion; "he is feeling much better now," and will be released next September.

You don't work a puzzle from the upper left-hand corner only. You work all of the pieces and parts of the puzzle that make sense to you at the time. If you did start at only one place and work linearly, as soon as you got to where the 'missing piece' was supposed to go, you are stopped dead in the water; never to move on. --That is, until the Wee People see fit to return the missing puzzle piece.

I liken Learning to taking the family to a Walt Disney movie (made by Walt himself, not this other crap); everyone, the young kids, the teenagers, and the adults, all get something from the movie--each is different, and the same. The young kids are entertained by what entertains young kids; same for the teenagers and the adults: that is to say, there is something there for everyone.  That was Disney's genius!

Likewise, learning is the accumulation of bits and pieces of knowledge and information; for everyone these can be different: it is the accumulation that is important.

Often the "Ah ha's" come later, but they come.

In more formal learning situations, one is discouraged from "reading ahead of the class,"  it is as though, if you are exposed to something--out of order--that you don't completely understand, it is harmful: what a crock!

Exposure is a large part of the learning process--that and TIME. Then come the "Ah ha's."

Oh yea, there is the absolutely most important required ingredient: Curiosity! Without Curiosity you may as well close the book and take up Taxidermy.

Read Ahead
Live dangerously: take a look at the Transistor page or the OpAmp page; Hell, check out the 555 Timer pages. You might be confused, and not understand everything you read; but it is a sure bet you will finish up knowing a little more than you knew--or at the least you'll have questions you didn't have before. Also, the fragments that you pick up now will appear out of nowhere later and fill in the gaps--HONEST!   If I'm lying, I'm dying!

When I started out learning this stuff, years ago, I learned a lot just by reading the ads in electronics magazines. Trying to read and understand the articles also helped--though oftentimes daunting. 

Finally, Don't judge yourself against others (you really don't know what they actually know--their claims are more often bogus); judge yourself against what YOU knew when you started out. Months from now it will blow your mind how far you have come.

Oh, yea: Have FUN while you are Learning. FUN is the most underrated and least appreciated part of Learning!!

OK, I feel better now; lets get to it...

Oh, by the way, I will be PRESENTING the following in as Linear/Sequential way as I possibly can.

gaw 
 

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.Electricity: In the Beginning
Part 2 of 2 -->
TOC
LINKS:
---INTRODUCTION ---Drop Cord Story ---Resistor Page
---In the Beginning --- ---Inductor Page
---E R I  VOLTs --- ---Capacitor Page
---E R I  OHMs
---E R I  AMPs
pop ups
---What is D.C., A. C. ---Water Modepop up ---555 Timer  pop up
--- ---Fun with Resistors  pop up ---Reading Schematics pop up
--- ---Resistor Color Code  pop up ---Wave Action  pop up
--- --- ---Parts etc. pop up

Some Pictures are worth 1024 words

   
   
"R" = Resistance
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.E-R-I--

E-= Voltage-R-= Resistance-I-= Current.
Part 2 of 2 -->
TOC
LINKS:
---INTRODUCTION ---Drop Cord Story ---Resistor Page
---In the Beginning --- ---Inductor Page
---E R I  VOLTs --- ---Capacitor Page
---E R I  OHMs
---E R I  AMPs
pop ups
---What is D.C., A. C. ---Water Modepop up ---555 Timer  pop up
--- ---Fun with Resistors  pop up ---Reading Schematics pop up
--- ---Resistor Color Code  pop up ---Wave Action  pop up
--- --- ---Parts etc. pop up

E-Voltage

A.K.A., ElectroMotive Force (EMF), Potential Difference, the unit used is the Volt
Voltage is an Excess of Electrons
come out and play  seeking come out and play
a Deficit of Electrons (Holes)
Two kinds of Voltages, Direct and Alternating,
     D.C.  Direct Current
     A.C. Alternating Current
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Hip Boots, for when it gets Deep!Electricity is associated with electric charge, a property of certain elementary particles such as electrons and protons, two of the basic particles that make up the atoms of all ordinary matter. Electric charges can be stationary, as in static electricity, or moving, as in an electric current.
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R-Resistance

Resistance to the Flow of Electrons, the unit used is the OHM, symbol:
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Insulator
Very High Resistance
Water
Moderate to Low Resistance
Pure water is an insulator, it is the impurities that cause it to conduct; salt water being an extreme example.
Conductor
in the form of an Electric Cord
Very Low Resistance

Some Well Known instances of using Resistance


Filament Close Up
Light Bulb Tungsten Filament
   
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Hip Boots, for when it gets Deep!Resistance is a property. 

A Resistor is an object, a thing that has the property of Resistance.

An extension cord has Resistance but is not necessarily a Resistor.

Resistors are used in circuits for their resistive properties. 

Below are some Resistors:

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1/4 Watt
  "Fixed"
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Single Turn Trimmer
"Pot"
Multi-turn Trimmer
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Fixed 
Symbol
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Potentiometer (Pot)
Symbol
Potentiometer
Resistor Color Code  pop up  

Potentiometer
Potentiometer Sliding Potentiometer
     
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Potentiometer, A.K.A., Pot, Volume Control, Brightness, Contrast, etc.

Potentiometer, as in Potential Difference
Potentiometer: voltage divider: a resistor or series of resistors provided with taps at certain points and used to provide various potential differences from a single power source. --webster

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Pot wired as pot
Pot wired as Rheostat
A.K.A., Voltage Divider 
Varies Voltage
 A.K.A., Variable Resistor
Varies Current
 
Resistors as
Voltage Dividers
Ratio = 1 : 1
Ratio = 3 : 1
Fixed Resistors configured as a Voltage Divider, 
note how Voltages relate to Resistances 
Variations on 
a Theme
Reostat Rheostat as Transistor
 Two Resistors: Lamp Filament & Rheostat
Fixed and Adjustable Power Resistors   configured as Voltage Divider
(Crude Transistor Analog)
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Hip Boots, for when it gets Deep!The use of  Resistors is not a very efficient method of changing voltages; e.g., if you have a 12 volt battery and you wanted to power a 6 volt bulb, you would put a Resistor of the appropriate value between the positive lead of the battery and one lead of the bulb (in series).

The bulb would now be powered at 6 volts: the remaining 6 volts (of the 12 volt battery), would be "Dropped" across the Resistor.

Using this method of voltage reduction, the Resistor would consume energy; in point of fact, the amount would be exactly the same as consumed by the bulb. The energy consumed by the Resistor would be in the form of Heat, and would be considered wasted..

For more on Voltage Dividers (pop up); also See the Resistor Page-----
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Resistance is Determined partially by Composition, 
and is inversely proportional to Cross Sectional Area
Note that Resistance is Also proportional to Length
Resistor Page Resistor Color Code  pop up
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I-Current

A.K.A., Electron Flow, the unit used is the AMP
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Battery

Electron Flow
When the two terminals of a battery are connected by a conductor, an electric current flows. One terminal continuously sends electrons into the conductor, while the other continuously receives electrons. The current flow is caused by the voltage, or potential difference, between the terminals. Voltage is measured in units called volts. Another name for a voltage is electromotive force (EMF).
Opposites Attract so they say
Battery's Terminals of Opposing Polarity:
Electrons = (-) Charge / / Holes = (+) Charge
  Negative terminal has Excess of Electrons;  Positive terminal has Deficit of Electrons, A.K.A., Holes
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The Direction of Current Flow-has changed several times over the past ~50 years. 

Until solid-state electronics, current flow was electron flow, which flowed from Negative to Positive, e.g., in the case of a vacuum tube, electrons bowling off of a hot Negative Cathode being attracted to the Positive Plate; all this controlled by a Biased (more positive than the Cathode, but less positive than the Plate) Control Grid. 

In solid state devices there are two terms used that complement one another: Electron Flow, and Hole FLow. good luck

Electron Flow: electrons (negative charge) moving from Negative to Positive. 

Hole FLow: The deficit of electrons (positive charge) moving from Positive to Negative. 

Presently, most speak in terms of Current Flow as being from a Positive source to Negative (Ground) return. 

Take Care in what is referred to as "Ground." 

Ground and Negative are not necessarily synonymous; that is, Ground can be a relative designation. 

Typically circuit parameters / measurements are in REFERENCED to Ground. 

One can have both Positive and Negative power both of which are referenced to Common or Ground. 

Common and Ground are often the same but don't have to be... Huh?  Confusing ain't it... 

Electrons flowing in a wire don't travel through wire at near the speed of light as is sometimes depicted. 

Simply speaking:  When an electron is attracted into a wire, it "bumps" a free electron (one that is free to swap orbits) into an adjacent free electron next to it and so on till a free electron "falls" out the other end. 

EXAMPLE:  A drinking straw full of BBs: put one more BB in one end, immediately one BB is forced out the other end. 

Though, electrons move through the wire slowly, the EFFECT is as though they move very fast: one in--one out, though they are not the same electron. 

Electron Flow, D.C.
The Animation depicts Electrons flowing through a wire in one direction: D.C.
Individual Electrons don't actually move at (near) the speed of light (C) in the wire, but as Electrons enter and exit the wire the EFFECT is the same.  It can be likened to Wave Action pop up.
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Electron Flow, A.C.
Animation: Electrons flowing through a wire, Alternately, in Oppersite Directions: A.C.

 - --Easy to remember Simplified OHMS LAW-((Power is missing for simplification)
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.E-R-I-Continued...

--Story of the Humble Drop Cord 
Part 2 of 2 -->
TOC
LINKS:
---INTRODUCTION ---Drop Cord Story ---Resistor Page
---In the Beginning --- ---Inductor Page
---E R I  VOLTs --- ---Capacitor Page
---E R I  OHMs
---E R I  AMPs
pop ups
---What is D.C., A. C. ---Water Modepop up ---555 Timer  pop up
--- ---Fun with Resistors  pop up ---Reading Schematics pop up
--- ---Resistor Color Code  pop up ---Wave Action  pop up
--- --- ---Parts etc. pop up
 ..
Voltage E   VOLT Electrons exerting a Potential Force, 
ElectroMotive Force (EMF)
Current I   AMP A Flow of Electrons
Resistance R   OHM A Real Physical Property resists the flow of Current
Power P   WATT Electrons flowing through a Resistance (load)
generates heat, does Work...
Of these entities, Resistance (R) and Voltage (V) are the only real physical properties; the rest--for the most part--are the result of Voltage's encounter with Resistance

Resistance is the property of a material to resist the flow of Electrons.

Everything has this resistive property: Air resists greatly the flow of electrons, but they do flow--especially if you are swinging a "nine-iron" on a hilltop, under low hanging dark clouds in the summertime!

Copper wire also resists the flow of electrons--but not very effectively; it makes a good Conductor.

Superconductors[1] are the only materials that DO NOT resist the flow of electrons.

Speaking of the flow of electrons, that is the definition of Current, which is expressed in AMPS (I).

And, you guessed it: Electrons exert a potential force measured in VOLTS and--you're ahead of me--is called Voltage.

WOW, that was too easy; we've covered it all in a few short sentences!

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O p p s !

Oh yea--except for POWER.   --Duh...

POWER, is the result of VOLTS, and OHMS, all getting together!

That is, the Energy released by Electrons (I) flowing through a Resistance (R), the number of which being determined by the Electron potential (E). --Huh? What did he say Betty Sue?
He said that [I = E/R] therefore [P = I x E]. Oh...

---------Ideas---------

OK, you have a 100 Watt light bulb in a drop cord (Drop Light); You plug it in to the 120 VOLT wall outlet  and turn it on. 

The light bulb offers a resistance to the 120 volt (electron potential) flow of electrons coming out of the wall socket--they're just sitting there doing nothing, until they find a path Home...

If the light bulb's resistance is too low the fuse will blow! 

If the light bulb's resistance is too high, not much will happen; 

But, if the light bulb's resistance is "Just Right," it will consume 100 WATTS of Power, to produce energy in the form of light; also, it gets hot as Hell--put your tongue on it, you'll see what I mean.

The light bulb/Resistor performed a useful function: it put out light to read by, and it also produced Heat. Heat that is thought of as "Loss," is technically still light, but at a wavelength few can read by. InfraRed

And, by the way, that drop cord wire (Drop Light) is also resistive and will get warm, which is Loss--wasted energy. 
 
 
Illustration of "Voltage Drop," A.K.A., IR Drop
Hear what Mrs R.J. of Duluth had to say:
        "That LOAD certainly made my flowers Grow."
Part 2 of 2 -->
TOC
LINKS:
---INTRODUCTION ---Drop Cord Story ---Resistor Page
---In the Beginning --- ---Inductor Page
---E R I  VOLTs --- ---Capacitor Page
---E R I  OHMs
---E R I  AMPs
pop ups
---What is D.C., A. C. ---Water Modepop up ---555 Timer  pop up
--- ---Fun with Resistors  pop up ---Reading Schematics pop up
--- ---Resistor Color Code  pop up ---Wave Action  pop up
--- --- ---Parts etc. pop up
------------------------------To Part 2 -->

© 1999  -  2011  Questions or Comments about  this site  webmaster


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