My LEGO Nexus Organization

This is the topic is a class on Electric Engineering, the teacher, who I am patiently waiting for let me make the topic for this, for now. *Watches clock*

Good afternoon class.

Today is the first day of ECE 201.  Because none of you have the book, there will be no homework.  There will be an occasional quiz though.  The first thing that I would like to discuss is units.  Everyone must have a fundamental understanding of units, before they enter any class.  First of all, we will be using the SI unit system in this class and not the English unit system.  Here is a basic list of SI units.

Chalk Board

                      Basic SI Units

Quantity          Basic Unit          Symbol

Length             Meter                m
Mass                Kilogram            kg
Time                Second              s
Electric Current  Ampere             A
Temperature      Kelvin               K
Electric Charge  Coulomb            C

End Chalkboard

Are there any questions so far?

There is no questions that I would ask. Sounds very clear and simple. *Writes in Onenote*

The next fundamental concept that you must learn is prefixes.  Here is a basic list of the SI prefixes.

Chalkboard

Note: This is not a list of all units.

Tera   10^12
Giga    10^9
Mega   10^6
Kilo      10^3
Milli      10^-3
Micro    10^-6
Nano     10^-9
Pico      10^-12

End chalkboard

Now, I must make this very clear at the beginning of the class.  AC stands for Alternating current, which means that the current level is a sinusoid, and DC stands for Direct current, which means that the current level stays constant.

Chalkboard

Sinusoid:

(http://radarproblems.com/chapters/ch05.dir/ch05pr.dir/c05p1.dir/sinewave.gif)

End Chalkboard

Now, we will start with the concept called "current".  Current is the amount of Charge that passes through a wire in any given period of time (be careful not to mistake this with flux [the amount of a substance or field that passes through an area in a given period of time]).  In other words, Current, which is represented by the symbol "i" is equal to the derivative of Charge, which is represented by the symbol "q" with respect to time.

Chalkboard

(http://upload.wikimedia.org/math/d/0/e/d0ebe45e0d4ee6804adb323de39bf364.png)

End Chalkboard

If this equation is reversed, the Charge can be found to equal the integral of the current with respect to time.

Chalkboard

(http://upload.wikimedia.org/math/f/9/f/f9fadc913fd2a703972389b243951497.png)

End Chalkboard

Alright, that is all we have for today.  Next time we will discuss Ohm's Law.

Also, before you leave, we might have a quiz over units next time, so be prepared.

real, amazing... on upon Currents work, that can be mathematically interpreted. Thanks a lot for the lesson. ;D

And I'll be sure to sturdy for the quiz, It almost like the downloading of bytes, Kilobytes, megabytes, gigabytes, terrabytes, wasn't a japanese cable line hold terrabytes?

If you have any questions before the quiz tomorrow, I will be in my office (my inbox) so please PM me.

ECE 201 Quiz 1

10 Points - You may not use the internet to assist you during this quiz.

1.

Fred has 7 files on his computer, and would like to put them on a Flash Drive.

File 1: 19.3 Mega Bytes
File 2: .763 Giga Bytes
File 3: 94 Pico Bytes
File 4: 100 Milli Bytes
File 5: .113 Giga Bytes
File 6: 1428 Kilo Bytes
File 7: 1973 Mega Bytes

Fred has a 1 Giga Byte Flash Drive, and he wants to make sure that all of the files will fit on his Flash Drive.

a) Calculate the total amount of space the files will occupy.
b) Does Fred need a new Flash Drive?  If so, how large does the new Flash Drive need to be?

Assume that 1 Giga Byte = 1000 Mega Bytes.
Assume that 1 Mega Byte = 1000 Kilo Bytes, and so on.
1,2,3,4,5,6,7,8,9, and 10 Giga Byte Flash Drives are avaliable.

I hate you, scientific notations!!!!!

Oh.. I'm going to get this wrong...

a) Around 2 1/2 gigabytes, or 2,810,621,000.1000000000094 Bytes.
b) Yes he needs to change the flash drive into probably a 3 gigabyte for better access memory.

*notes to self: scientific notation is a force that should be reckoned with; and never miscalculate a pop quiz*

8/10.

The answer was close, but not correct.

I knew it, the pressure from a pop quiz.... scientific notation is widely used in chemistry and astronomy ain't it? As well as in this subject. To gain experience from this pop quiz may I know the answer? So I can learn in the future?

Oops, wrong topic

   

 

 

 

Is it...

Maple 13(That's actually a program)
Mathematica

I believe the answer is 2.8697280001 Giga Bytes.

I have Maple 9.5, Mathematica 5.4, and MATLAB 7.0

Hmm.. not bad...

AWW!!!! I want those.... *sobs* Your a student? To get a discount on those?

So when's the next lesson? Excitement is filling the air. :D

I got a discount on Mathematica and Maple.  MATLAB on the other hand.... well, a friend gave that to me.

ah.... well I hope it's useful, because i have seen it in action.... in youtube....

*Gets Microsoft Onenote for a lecture*

OK, now we shall begin the next class period.  We will be discussing Kirchhoff's Laws (not to be mistaken with Kirchhoff's Laws of Heat Transfer) and Ohm's Law.

Because we have already discussed the units and properties of current, we shall now move on to voltage (electric potential difference) and resistance, which is NOT to be confused with impedance.

Chalkboard

Resistance is measured in Ohms.  The unit is the capital Greek letter, omega: "Ω".

(http://www.mlno.org/index.php?action-post;topic=4597.0;num_replies=15)

Voltage is measured in Volts.  The unit is the capital letter, V: "V".

End Chalkboard

If you have not already learned about Potential Energy in physics, all the better for you.  There is a big difference in Electric Potential and Physical Potential.  

Chalkboard

The formula that relates Voltage, Resistance, and Current is Ohm's Law.

(http://upload.wikimedia.org/math/f/9/a/f9ae53a99f2b2b6a74146fb04fb3ff73.png)

(http://upload.wikimedia.org/wikipedia/en/thumb/d/de/OhmsLaw.svg/120px-OhmsLaw.svg.png)

End Chalkboard

We will now work an example using Ohm's Law.

Chalkboard

Circuit:
 
  i
--->

-----  
      |   +
      |
      \
      /    Vr
      \
      /
      |
      |    -
-----

The resistance of the resistor is given to be 5 Ohms.  The current flowing through the circuit is given to be 10 Amps.  Calculate the Voltage drop over the resistor, Vr.

V=IR

V=(5 Ohms)*(10 Amps)

V=50 Volts

End Chalkboard

Are there any questions so far?

Yes, What happened to the first image? Where is it?

After that and my coping the lecture, I'll ask more.

What first image?  Everything that's there is what I put there.

Oh... ok, No further questions.

That style looks like from wikipedia... legodac

Pop Quiz!

1.According to the International System of Units, what’s the official base unit for measuring electrical current? (Examples: meter measures length, second measures time.)
2.What 1970s science fiction film recounts electrical engineer Roy Neary’s long, strange trip to Wyoming…and beyond?
3. In 1844, Washington DC and Baltimore became the first American cities connected by what method of communication?
3. What Austrian-born electrical engineer, who patented a form of spread-spectrum still used in wireless communications, has a star on the Hollywood Walk of Fame?
5. German physicist Heinrich Hertz discovered and experimented with what form of electromagnetic radiation?
6. What device did Harold P. Brown invent in the late 1880s to help Thomas Edison publicize the dangers of alternating current?
7. The US Supreme Court upheld the radio-related patents of what inventor in June 1943, five months after he died?
8. After 1941, “radio direction finding” became known by what more popular acronym?
9. After the transistor was invented in 1947, it replaced what device in most electronic equipment?
10. Before inventing the Moog synthesizer, Robert Moog sold kits for building what other electronic musical instrument?


[spoiler]
1.ampere (or amp)
2. Close Encounters of the Third Kind
3. telegraph
4. Hedy Lamarr
5. radio waves
6. electric chair
7. Nikola Tesla
8. radar
9. vacuum tube (a.k.a. thermionic valve; also accepted “tubes”)
10. theremin
[/spoiler]

Sure, have a seat :).  

Also, I'm getting my pictures from Wikipedia.  I am cross checking them with my Circuits book to make sure that they are accurate.

Awww.... You said it before I modified my post.... and MsRR, forgot the Spoiler didn't work.

That was a nice quiz, but I wouldn't have given it to anyone who hasn't taken the first half of Magnetic Physics.

Magnetic Physics? Oh my *Faints* Does it have electric-magnetic physics, and how it is one of the four major forces in the universe? And how it's like Earth's, Sun's Plasma Magnetic field?

No offense, but it's very difficult for me to understand what you're trying to say.

 What is the difference between a Verilog task and a Verilog function?



Given the following Verilog code, what value of "a" is displayed?
always @(clk) begin
a = 0;
a <= 1;
$display(a);
end

Sorry... :-[

I was going to say when you said "Magnetic Physics" And I was imedeately thinking of..
Electric-Magnetism
The Earth's and Sun's Magnetic field
Electric Magnetism being one of the major four forces in the universe
And yea...


Legodac, what program is it?

Alright, now we will go over Kirchhoff's Voltage Law (KVL) and Kirchhoff's Current Law (KCL).

Just a quick thing that I want to tell everyone.  Eventually, you will probably abandon both of these laws, and switch to either Mesh Currents Law, or Nodal Analysis, depending on which one you like more.

KCL basically states that the sum of all currents entering a node, must equal the sum of all currents leaving a node.  I will make the analogy of pipes.  In the electric world, Ground is 0 potential or 0 Volts, and all current will be directed towards the ground node.  The same is true with pipes.  If you have a Y joint, and there are two flows coming in from the top two points of the Y, the same amount of flow will exit.  If any of you happen to have a Thermodynamics book, go ahead and look up Mass Flow rates, because the same principle is true here.  Here is a picture.

Chalkboard

(http://upload.wikimedia.org/wikipedia/commons/6/69/KCL.png)

And the forumla:

(http://upload.wikimedia.org/math/1/7/b/17bbbd9b6e69b94dab881bacae540191.png)

End Chalkboard

This concept is a bit difficult to grasp, so if you have any questions, please ask now.

Also, I have no idea what kind of programming that is.  I know MATLAB, PSpice, Action Script 2 and 3, and Maple....

Correct legodac. In the US we use V.

Ohm's Law defines the relationships between (P) power, (E) voltage, (I) current, and (R) resistance. One ohm is the resistance value through which one volt will maintain a current of one ampere.

( I ) Current is what flows on a wire or conductor like water flowing down a river. Current flows from negative to positive on the surface of a conductor. Current is measured in (A) amperes or amps.

( E ) Voltage is the difference in electrical potential between two points in a circuit. It's the push or pressure behind current flow through a circuit, and is measured in (V) volts.

( R ) Resistance determines how much current will flow through a component. Resistors are used to control voltage and current levels. A very high resistance allows a small amount of current to flow. A very low resistance allows a large amount of current to flow. Resistance is measured in  ohms.

( P ) Power is the amount of current times the voltage level at a given point measured in wattage or watts.

We will not use the symbol "E" to represent Voltage.  E stands for electromotive force, and that is only used in physics.

Wait that Formula in the lecture..... I know that.... well the first part... it's something to do with.... I forgot... May I ask what is that?

KCL or Ohm's law.

Also, it's going to be a bit difficult if all 3 of us are using different methods to teach... I don't mind letting you guys teach it, and I can teach Thermodynamics instead...

In Kirchhoff's Voltage/Current Law with that E, I seen that before...

My professor chastised us for using E to represent Voltage.

I mean the formula, Which right now I traced it back to something with factorials, Now I remember.

(http://upload.wikimedia.org/math/e/0/5/e0536762f4107b81d9b0e16d26b28cef.png)

First part of that equation, not the rest.

JWalker, please do not double post.. it is spam.

That symbol is the summation symbol.  It means the sum of all currents = 0.

MsRR, Wasn't there a topic, of "When it's ok to double post" But for this topic, everything is moving, and maybe time to modify a topic, isn't that fast, and maybe someone would over look that, which legodac miss my modified posts over two times, in this topic alone. now Back on topic shall we?


Oh!! Thanks!

Maple, that was for shops. We do not want chaos in the " classroom" so let's use the edit button please.


Jwalker, since we have members here from many countries, perhaps it is best to have some tolerance of that.

I didn't think of that... I'll take that into consideration now. 

Since I'm not the only person teaching here, would somebody else like to explain KVL?

Yea, I known it was for shops, but still.... Legodac missed my "What program you used?" After I modified my posts, two times... Must be bad luck... or many posts at the same time..

Yea.. I'm in another country with 110 for American, and 220 for this country, because with my accident with my AVR, and an American Computer with a 220 volt, and touching it, gives me spark, and..... BAM!!!! A sudden sparky sound, and my heartbeat.


Sorry for any rush, but do we have another lesson here? Because I have to go to bed, sorry, It's 1:08AM in a Monday, and lots of things to do.

Nah, I'll just leave it like this.  We'll go over KVL next time.

Kirchhoff's Voltage Law describes the distribution of voltage within a loop, or closed conducting path, of an electrical circuit. Specifically, Kirchhoff's Voltage Law states that:

The algebraic sum of the voltage (potential) differences in any loop must equal zero.
The voltage differences include those associated with electromagnetic fields (emfs) and resistive elements, such as resistors, power sources (i.e. batteries) or devices (i.e. lamps, televisions, blenders, etc.) plugged into the circuit.

Kirchhoff's Voltage Law comes about because the electrostatic field within an electric circuit is a conservative force field. As you go around a loop, when you arrive at the starting point has the same potential as it did when you began, so any increases and decreases along the loop have to cancel out for a total change of 0. If it didn't, then the potential at the start/end point would have two different values.

Positive and Negative Signs in Kirchhoff's Voltage Law
Using the Voltage Rule requires some sign conventions, which aren't necessarily as clear as those in the Current Rule. You choose a direction (clockwise or counter-clockwise) to go along the loop.
When travelling from positive to negative (+ to -) in an emf (power source) the voltage drops, so the value is negative. When going from negative to positive (- to +) the voltage goes up, so the value is positive.

When crossing a resistor, the voltage change is determined by the formula I*R, where I is the value of the current and R is the resistance of the resistor. Crossing in the same direction as the current means the voltage goes down, so its value is negative. When crossing a resistor in the direction opposite the current, the voltage value is positive (the voltage is increasing).

Kirchhoff's Voltage Law in action:
(http://z.about.com/d/physics/1/0/1/0/-/-/KirchoffVoltage.png) depicts a loop abcd. If you begin at a and advance clockwise along the interior loop, the Voltage Law yields the equation:
v1 + v2 + v3 + v4 = 0
In this case, the current will also be clockwise. Crossing the resistors will result in v1, v2, and v3 all being negative. Since you're crossing from negative to positive, v4 will be positive. If you consider the dotted line that has the R5 resistor, you get a total of three loops in the circuit. The first one has already been described. One loop is the largest loop and another is the smallest loop at the bottom, to yield the equations:
v1 + v2 + v5 + v4 = 0 (abcd taking the new path instead of R5)
v3 + v5 = 0 (the small loop cd)
The second equation indicates that v3 = -v5. This makes sense, because both currents will be travelling from c to d, so on the small loop you'll cross one resistor with the current and the other resistor against the current. If the resistors are of equal value, then the current in both paths will be equal.

K, oh, and a question, What grade level do you think studies... Cellular Respiration, Krebs Cycle, Photosynthesis in detail(not the simple)?

Wow.... MsRR.... *Copies whole thing and posts it into Microsoft Onenote* I just don't have enough time to review that all...

Go to sleep.. it will be here tomorrow :)

Ah... Well it is "tomorrow" already, but going off topic, what kind of grade level studies Cellular Respiration, Krebs cycle, mitochondria, and the complex photosynthesis of the Calvin cycle/Light-Dependent Cycle?

So many years since I took those type of classes, I think JWalker would be better able to answer that.

Ah.... Well... I wonder if class would be in session somewhat... *waits patiently*

Sorry, I caught a cold :(.  I don't think I'm gonna be able to give any more "lecture" until I get better.

Oh...  :( I'm quite sorry to hear that, but oh well... I can try doing some lua scripting language help....