Log in lkchen9699 8 years agoPosted 8 years ago. Direct link to lkchen9699's post “I think the right-hand si...” I think the right-hand side of the equation should be dVin/dt if you define Vin as the voltage. And this equation is not KVL; it is the equation for the rate of change of voltage. • (24 votes) JensOhlmann 8 years agoPosted 8 years ago. Direct link to JensOhlmann's post “at Ikchen9699 you are rig...” at Ikchen9699 you are right. The equation comes from the eqaution VL+VR+VC = Vin (13 votes) samananwar 7 years agoPosted 7 years ago. Direct link to samananwar's post “Why inductor is used in t...” Why inductor is used in the AC circuit? • (2 votes) APDahlen 7 years agoPosted 7 years ago. Direct link to APDahlen's post “Hello again Sama!There ...” Hello again Sama! There are a few ways of looking at this: First from a radio engineer's perspective: Inductors are your best friend. They along with capacitors allow us to form tuned circuits. These circuits are the building bocks upon which all radio transmitters and receivers are built. Without inductors you would not be able to tune a radio. From a power supply engineer: If you are using a computer be thankful we have inductors. They are the essential to the construction of power supplies. Inductors and their close cousin the transformer are found everywhere. In fact if you are using a computer you a employing dozens of inductors in the chain of power supplies that take the wall outlet power and convert it to a regulated DC voltage for the main CPU. You will also find inductors in the LED lights that light your room. Finally, lets see what a power grid engineer has to say: It would be nice if we didn't have inductors but they are everywhere. The large generators at the power plant act as inductors, the power lines have inductance. Yes, a simple wire will act as an inductor! Also, almost every AC motor on the grid acts as an inductor. My job is difficult as I must keep track of and supply the imaginary (aka reactive) power that all of these inductors require. This is where phase comes into the equation. All of these inductors make the delay the phase of the current relative to the voltage. That's OK by me as I can talk about cool things like phasors, real power, reactive power, VARS, VA, symmetrical components, lagging power factor, and my personal favorite the syncrophasor! Please leave a comment below. Enjoy! Aaron (15 votes) Vish 8 years agoPosted 8 years ago. Direct link to Vish's post “are these voltages or rat...” are these voltages or rate of change of voltages? • (5 votes) Tompap2007 8 years agoPosted 8 years ago. Direct link to Tompap2007's post “It really seems like it i...” It really seems like it isn't KVL. When we didnt have any voltage source, the equal of KVL was zero, and if we tried to get the rate of change of the KVL equation, this was equal to d0/dt = 0. So now that the second part of the equation is Vin, we should have d(Vin)/dt, not just Vin. Could we have an explanation over this please? (6 votes) samananwar 7 years agoPosted 7 years ago. Direct link to samananwar's post “ac signal is the function...” ac signal is the function of voltage or time or current? • (4 votes) APDahlen 7 years agoPosted 7 years ago. Direct link to APDahlen's post “Hello Samananwar,Both v...” Hello Samananwar, Both voltage and current vary as a function of time. Mathematically you could talk about voltage as V(t) = Asin(2πft + Θ). Here A is the peak voltage, f is the frequency and Θ is the phase shift. We could make a similar equation for current. Regards, APD (4 votes) Peter Borkowski 7 years agoPosted 7 years ago. Direct link to Peter Borkowski's post “plz see Professor Shanka...” plz see Professor Shankar's introduction into AC LCR circuits https://www.youtube.com/watch?v=cS83YUpcEsY • (0 votes) Willy McAllister 7 years agoPosted 7 years ago. Direct link to Willy McAllister's post “I'm glad Professor Shanka...” I'm glad Professor Shankar's presentation was helpful to you. Every teacher takes a slightly different approach to difficult problems. I will see what I can learn from his presentation. (8 votes) samananwar 7 years agoPosted 7 years ago. Direct link to samananwar's post “Why phase difference betw...” Why phase difference between two alternating quantities is more important than their actual phases? • (3 votes) Willy McAllister 7 years agoPosted 7 years ago. Direct link to Willy McAllister's post “There really isn't a stro...” There really isn't a strong definition of "actual phase". Phase is always a relative measurement between a signal and a reference signal. If we have one AC signal we get to choose what time we label time = 0. It can be at a peak or trough, or where the signal crosses 0 volts. It is an arbitrary choice. When we start to think about a second AC signal, one of the important things is its phase relationship with the first signal. This is what we call relative phase. (2 votes) Fabrizio Lopez 6 years agoPosted 6 years ago. Direct link to Fabrizio Lopez's post “I have an existential dou...” I have an existential doubt, not about the video but about the alternating current. I do not know where to put the question, excuse me. I hope someone can help me with this doubt :( thank you very much in advance. • (3 votes) Balwant Singh 6 years agoPosted 6 years ago. Direct link to Balwant Singh's post “in India and rest of the ...” in India and rest of the world we are using 50 hertz and 230 volt power supply and in america and japan they are using 60 hertz and 120 volt power supply. question 1. why is it so?? • (2 votes) Willy McAllister 6 years agoPosted 6 years ago. Direct link to Willy McAllister's post “It seems that the reason ...” It seems that the reason for 50 and 60 Hz is due to a set of decisions by the major power-generating companies in Europe and the US. Once a big company settled on a frequency and started making generators, everyone else followed along. Here's the reference I found: http://www.djtelectricaltraining.co.uk/downloads/50Hz-Frequency.pdf (2 votes) kishorehari654.hk 6 years agoPosted 6 years ago. Direct link to kishorehari654.hk's post “What is meant by positive...” What is meant by positive phase sequence, negative phase sequence, and zero phase sequence in AIR CIRCUIT BREAKER • (2 votes) 2T48004U a year agoPosted a year ago. Direct link to 2T48004U's post “Too bad they don't have a...” Too bad they don't have any quizzes or unit tests for this. I got my exam this week would've been nice to get the practice other than using my assignments and labs from my class already • (2 votes)Want to join the conversation?
if we write the VL,VR and VC as differentials. That looks like that
L dI/dt + R*I + 1/c *∫Idt = Vin. This equation is called intregro-differential equation because of the integral. To make this kind of equations to a differential equation take the derivative on both sides. Now we have the equitation L d^2I/dt^2 + R* dI/dt + 1/c * I = dV/dt.
your derivations is really confusing , the results are the same but the road leading to them is very hard ,
Now my question: Leaving away the stationary state, how does the current to go from the positive pole of the source to the negative pole (assuming that the distance is much greater than the wavelength of the signal as in a transmission line for example or a high frequency circuit), if the polarity varies and therefore, the direction of the current also and due to this, the current should be moved same quantity of meters in one direction and the other. So, how the current can arrive to the "final" of the circuit?
question 2. why not 70 hertz, 80 hertz or less than 50 hertz. why we are choosing 50 hertz and 60 hertz only.
See Also
AC Theory 3: Lesson 6 - Understanding How The DC Generator Works Flashcards by Jordan KnutsonAC Theory 3: Lesson 7 - Understsanding The Design And Function Of AC Generators Flashcards by Jordan KnutsonBasic AC Theory – ElectronX LabAC Theory 3: Lesson 5 - Introduction To Generators Flashcards by Jordan Knutson