Electric Engineering 201

[Maplen13]

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*

[[5025]]

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.

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                      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

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Are there any questions so far?

[Maplen13]

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

[[5025]]

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

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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

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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.

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Sinusoid:



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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.

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

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

[[5025]]

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

[Maplen13]

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

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?

[[5025]]

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

[[5025]]

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.

[Maplen13]

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*

[[5025]]

8/10.

The answer was close, but not correct.

[Maplen13]

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?

[Legodac]

Oops, wrong topic

   

 

 

 

[Maplen13]

Is it...

Maple 13(That's actually a program)
Mathematica

[[5025]]

I believe the answer is 2.8697280001 Giga Bytes.

I have Maple 9.5, Mathematica 5.4, and MATLAB 7.0

[Maplen13]

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.

[[5025]]

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

[Maplen13]

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

*Gets Microsoft Onenote for a lecture*

[[5025]]

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.

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



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

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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.  

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





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

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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

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Are there any questions so far?

[Maplen13]

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

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

[[5025]]

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.