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Posts posted by Achilles

  1. In each of the equations there is voltages subtracted which I don't understand.

    Like in Equation 2 which you quoted:

    V2 - V1 and V2 - V3...  This is part I don't understand and wasn't explained to me.

    And it is actually voltage minus another voltage not a current. It is V/R for all instances in the equation which its sum is 0. I am asking why he minus the voltages.

  2. Ok but I am specifically talking about the Node Voltage Method, which happens to work out great for this circuit. The problem which you stated as a good thing but is bad thing in my teacher eye well not bad but not great... is that you got to write lots of equations. This only requires 3 equations and Kirchhoff law requires like 6 in total equations (loop equations and node equations) I think.... 

    My question requires you to know and understand the Node Voltage Method because I am asking why you subtract different voltages from each other. Please stay on topic thanks. I understand what you mean but that is not about my circuit and not about my question. Thank you though.

  3. I am not a good at explaining things so I will just leave this video to show you what I mean. Yes I understand Kirchhoff doesn't have node voltage but the Node Voltage Method which is common practice and has many YouTube videos and articles on google about it. Also my teacher starts off with the assumption that all currents are going out of the node and only in (which is negative) when there is a current source that is pointing into the node. So it is not Kirchhoff Current or Voltage Law but it uses his Laws in a different way.

    Khan Academy - Node Voltage Method

    I know some won't watch video cause it aint 2 minutes or something, I have short attention span as well, but if you want to understand Node Voltage Method than watch the video. And then maybe you can help me with my question :P

  4. 9 minutes ago, studiot said:

    Thank you for confirming this.


    Before we proceed do you know what a current source is as a circuit element?

    I ask because someone has drawn that circuit incorrectly so it it is missing some information.

    No sorry I was just given the problem as is and have been using current source simply as a current source in a circuit diagram without understand what it is in reality if that is what you asking. Can you tell me what is wrong thanks.

  5. It's called the node voltage method it applies Kirchhoff current law and that 5 and 7.5 is called current source.

    Go YouTube it if you want to understand it

    IN this method you are substituting current which is I for V/R and so you can isolate the variable V which is Voltage which is what the problems is usually asking. It supposedly is faster way than Kirchhoff Current/Voltage Law. That is what my teacher says.

  6. I watched a short video where it said most simple it is when a magnetic field effects the flow of electrons and makes it more charged on side than the other producing a voltage.

    He explained that there a various types of hall effects but this one was most simple one to explain.

    Please explain for a layman. 

  7. Derived from this circuits 3 nodes using the NODE VOLTAGE METHOD are 3 equations:

    1) V1- -40/12 + V1/25 + 5 + V1+V2/20 = 0

    2) V2-V1/20 - 5 + V2-V3/40 - 7.5 = 0

    3) V3-V2/40 + 7.5 + V3/40 = 0

    My question is what is the method for subtracting voltages from each other. Like why in the first equation is it V1 - -40 or in Equation 2 why is it V2 - V1 or Equation 3 V3-V2... etc. The guy teaching Circuit Analysis does not explain why he does this. Please explain to me. I will be very thankful.


  8. The reason I ask is because I am doing Circuit Analysis and the guy uses Matrices to solve for the variables. I think he just wants me to buy the other other tutorial on Matrices that's why he introduce them into Circuit Analysis...  Anyway since it is solving for unknown variables (I did some high school algebra but that is it) can you use algebra substitution method instead of using a matrix/matrices to solve for unknown variables.

    I have not learnt Matrices yet.

  9. "If you can't explain something simple enough for someone to understand then you don't know it well enough" 


    "If you can't explain something to someone then you don't understand it well enough"

    Takes away the "simple" cause maybe it aint a simple concept to them, but nonetheless can still be explained. I mean that is how we all learn in the first place right.

  10. Do you think they make a lot of profit?

    Just finished reading an article about artificial diamonds made in the lab and it is exactly the same structure as a diamond that took billions of years to produce. Price is said to be 30 percent less for artificial diamonds.

    That should be some decent money right there and good for a buyer who doesn't really care for it to be billions of years old...


    link: https://www.ritani.com/blog/diamonds/diamond-faq-lab-grown-diamonds-vs-real-diamonds/

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