Nan,

I believe some corrections are in order for your power tutorial.
In short, Power is a measurement of Energy used in one Second.

A more general definition of power is the amount of energy transferred per unit of time .
Torque (rotational energy) = Force * Distance

It is a false presumption to assert that because different quantities are described by the same basic units, they are the same thing in different forms.
Torque is NOT rotational energy. Torque and energy both have the same units, but in translational energy, force is applied along the path it moves. The force component of torque is applied at a perpendicular direction to a radius. One can put a tremendous amount of torque on a stubborn nut with a wrench, but if it does not turn, then no rotational energy is involved.
Ampere (Unit of Electromagnetic Curent Flow)

Current is charge flow. Current flow is charge flowing twice (charge flow flow), which it does not do. See my previous posting entitled Conventional Current Direction. An ampere is a unit of charge flow or simply a unit of current.
In all cases Energy/Power is conserved. Be reminded in this example, the Power you put into walking across the room is determined by Energy exerted divided by the time you took to do so.

Energy is conserved, power is not. Energy has a physical manifestation, power does not. Power is the rate of energy transfer, and not something that can be "conserved".
Notice we dont care just what the resistance is, only thing here that matters is How Hard (voltage), and How Fast (current)!

Resistance is very important aspect of a circuit; ignore it at your peril. Charge flow is very slow in a wire, but the amount of charge that moves is very high. Voltage is one of the determining factors for the amount of charge flow.
Power companies sell you power to do your every day life.

No they don't, they sell you energy. "Power companies" is a misnomer. They should be called energy companies. They meter the amount of energy sent to customers, and charge them based on that amount of energy, not on how fast they deliver it.
However, there is a tremendous pressure upon them (500,000V) giving them alot of potential to do alot of work if allowed. Since the bottom line is nothing is moving much on power lines, the result is that there is not much "friction" from electrons bouncing off copper atoms, which would create heat and drain POWER from the source (as we saw happening in the first example)!

You mean drain energy, don't you?

Pressure is force per unit area, which does not apply to electric circuits. Voltage is electromotive force or electric potential. The resistance that occurs when electron flow is impeded is not mechanical friction.
I hope this gives you a good feel for what Power is and how it ties into electronics.

Have you defined what energy is yet? Ratch
Posted on 2003-05-09 09:59:01 by Ratch
Energy is the capacity of a body to do work.
Power is the rate of work done or energy converted.
Posted on 2003-05-09 11:11:55 by roticv
Ratch, thank you... i see you are well versed in a physics background. If you want to hang on my every word from this view, then i submit myself and my efforts to you. Your 100% correct.

However, im not writing this to make my own physics text. Im only trying to give people a first introduction to these concepts and keep it as simple as possible. I have freely bent hard and fast physics in some areas to keep the topic from convoluting (in my opinion). My aim is to give a principal understanding only not create A+ physic grads...

It took me approximately 2 hours to write that. If you want to write your own i encourage you (and anyone else) to do so. If you would like i will add a disclaimer to future tutorials that i write to keep this clear for all readers...

Regards,
:alright:
NaN
Posted on 2003-05-09 20:32:01 by NaN
Nan,
I don't mean to upstage you, but I think it is more important to be accurate than it is to be "easy and simple". It is especially important for those starting to learn the basics of things electrical to have an accurate knowledge of what is really going on. Actually, one can explain elementary electrical subjects in a easy to understand manner and still be accurate. Working against this goal is a hell of a lot of misuse of electrical terms, as I pointed out in "current flow". Another is an endemic misunderstanding in electrical science of what certain terms like "conventional current direction" mean, and how they came about. Still others are relationships such as V=I*R being wrongly called Ohm's law, and which I have not yet explained why that is an error. As you can see, accuracy is a problem, and a big one.

I think that you are reinventing the wheel in attempting to explain basic electrical concepts. There are so many explanations and texts available that cover this subject, that your effort is lost among the many. Perhaps it would be better to give a good link or quote on a particular subject, or ask a guru to write something about it. Then others could constructively criticize it for accuracy and completeness; which is important. Ratch
Posted on 2003-05-09 23:14:35 by Ratch
Well i asked, write one...

I just want tuts up here.. how they get here doesn't bother me a bit...

Please.. write some tuts.. you seem like you know how to get it done right.. so go for it...

(I will close and skicky them for you if you want)

:alright:
:NaN:
Posted on 2003-05-10 08:57:27 by NaN
Ok, I will try.

To everyone who reads this form:
If you have a elementary question about a particular aspect of electrical science, try to find the answer in a good textbook or web link. If you cannot find enough or the right quality of information, then post your query here, and I will try to write a concise and cogent tutorial for it. Do not, however, expect my tutorial to give you a comprehensive education in this subject, especially advanced concepts. This form should be driven by requests and responses, not whatever I feel like writing about on a particular day. Also keep in mind that I am only one person who is not infallible and whose time is limited.

So, what do you all want to know about things electrical that you cannot find out by yourself? Ratch
Posted on 2003-05-10 09:34:17 by Ratch
Well, myself, i was about to move into Diodes, then Transitors and ultimately lead up to Op-Amps...

If you wish to save me the burden here this would be my suggestions... but its really up to the rest of the board...

:alright:
NaN
Posted on 2003-05-10 10:19:52 by NaN
Each one of those components is a HUGE subject, and well covered ground by others who have gone before us. I await specific questions. Ratch
Posted on 2003-05-10 10:47:46 by Ratch
Not necessarily.. well from my point of view anyways... all three can justifiably made simple enough to be put to practice... especially diodes but i dont plan on a die-hard physical approach...

:alright:
NaN
Posted on 2003-05-10 11:33:28 by NaN
Nan,
OK, which diodes are you going to cover?
a. silicon diode
b. germanium diode
c. zener diode
d. power diode
e. Schottky barrier diode

Which transistor types?
a. junction transistor
b. field effect transistors (IGFETS & MOSFETS)

What op amps circuits?
a. amplifiers (inverted and non-inverted)
b. integrators
c. differentiators
d. filters
e gyrators
f. oscillators

You have a BIG job ahead of you. Fortunately a lot of the work has already been done by other people who have written texts and posted about it extensively. Ratch
Posted on 2003-05-10 14:46:25 by Ratch
Which diodes?

a. silicon diode
b. germanium diode
c. zener diode

Which transistor types?

a. junction transistor
b. field effect transistors

What op amps circuits?
a. amplifiers (inverted and non-inverted)

When i discuss AC circuits, i will come back to these, as well as transistor amplifiers.

b. integrators
c. differentiators
d. filters



Now,
Are you afraid to talk about these? Because this B.S'n is not making any tutorials. So far as i see it your all talk. Im not going to critique and critisize you for what you leave out (as you do me). I even offered you my serviced to help it get noticed. However, all im hearing is but, but, but... You talk a big game, so i say go for it and stop harrasing me.

Proove me wrong. I dont want to single handedly write all the tutorials here. If you *can* write something of value, then we all win with another point of view and an asset to a topic. If not, you have to enjoy what i write, cause your badgering isnt stopping me.

:NaN:
Posted on 2003-05-10 16:49:58 by NaN
Nan,
I don't feel like building the wheel again, and I don't consider myself a teacher. Go ahead and write your tutorials. I won't say anything about them unless someone specifically asks me a particular question about a point that I can answer. Fair enough? Perhaps it is best that any questions appear in the Electronics forum and refer to the Theory forum if necessary. Ratch
Posted on 2003-05-10 18:23:51 by Ratch
NaN,
Nice explanation!
Would you be so kind to add something about:
Why in my European house all wires and equipment are so thin and elegant
and in my Canadian house all wires and equipment are so big,hot and ugly?
Why in Europe you can't see transformers on the streets
and here they are as statues of the stupidity in every street?
What about the size and price of wires and cables in Canada and Europe?
Why Canadians haven't hermetic windows and internal doors and
how many additional energy they waste (and pay about it of course)?
Why Europeans use one international measure system (SI) and
Canadians two (one archaic plus SI)?

Regards,
Lingo
Posted on 2003-05-12 19:35:21 by lingo12
money.

if things are cheap you don't care about waste. when things are expensive you have to.
Posted on 2003-05-13 08:26:40 by Hiroshimator
lingo12,

Im not sure how to take you reply? Are you taking shots at me being Canadian? Or what?

:NaN:
Posted on 2003-05-14 12:41:36 by NaN
NaN,
"Are you taking shots at me being Canadian?"
Don't be stupid...I have a Canadian citizenship too and we aren't guilty...
Just try to explain why some countries use 110v, other 220v and which one is better?
In Canada we waste energy as a heat and pay it (my march's bill was with $200 bigger)
because we work with two times bigger AC too...etc

Regards,
Lingo
Posted on 2003-05-14 17:57:13 by lingo12
To transfer power, higher voltage uses less current.

Less current translates in less heat losses in the power lines.

So 220V outlets and wiring will have 1/4 the heat loss as 110V lines would. (I^2*R). Current halfs from twice the voltage.

However, 220V is not all that fantastic either. You still have to have transformers in Europe. They may be burried below ground, or often little green boxes on the side of the road (with a heavy metal casing).

Residential power is typically 13.8kV (if i remember correctly). Those pole top transformers transforms two of the three phases per house (providing two 120V phases, 120' out of phase).

Your stove and dryer uses phase-to-phase voltage which is Root(2)*120 = 208V
The common lead between each phase is grounded and considered neutral.
Individual phases power outlets/lights at 120V, single phase.

However, I know very little about Europe's power system...

:NaN:
Posted on 2003-05-14 22:37:30 by NaN
220V here
Posted on 2003-05-15 07:20:30 by Hiroshimator

I think that you are reinventing the wheel in attempting to explain basic electrical concepts. There are so many explanations and texts available that cover this subject, that your effort is lost among the many. Perhaps it would be better to give a good link or quote on a particular subject, or ask a guru to write something about it.


I dont want to get engulfed in a flame war by saying this but i really enjoyed Nan's tutorials. I have seen a lot of text covering electronics but it looks real boring and i personally want to run away when i see it.
But for the first time i seem to be actually enjoying and wanting to read about electronics. I personally dont care too much if the tuts are a bit inaccurate, but as long as they are written the way Nan writes its fun reading them. After all whats the use of being dead accurate if people are not going to read the stuff.

I really appreciate his effort and hope he continues with his good work.

:alright:
Posted on 2003-05-18 09:21:23 by clippy
gladiator,

I personally dont care too much if the tuts are a bit inaccurate....
In the future, please indicate whom you are quoting.

I know a few folks who agree with you. I always ask them; Why not have both accuracy and a little entertainment? In any case, would you be concerned about educational quality if your local school or institution of higher learning stressed style over substance? Some subjects just are "hard", and it takes determination and commitment to master them. Ratch
Posted on 2003-05-18 09:51:10 by Ratch