Nodal Analysis Example-Independent Voltage Source (Harder)
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- เผยแพร่เมื่อ 11 ม.ค. 2012
- Shows how to do nodal analysis with an independent voltage source where a supernode must be used. More instructional engineering videos can be found at www.engineeringvideos.org.
This video is licensed under the Creative Commons BY-SA license creativecommons.org/licenses/b....
THANK YOU! I have a midterm on Monday and nodal analysis with supernodes and all that have been giving me trouble, this cleared a lot up.
Thank you, you save our whole semester.
If you are viewing this as a circuits student (i.e. in preparation for an exam) I suggest you look up how to do matrix algebra with whatever calculator you intend to use on your exam and get some good practice with that. Both the TI-84 and TI-89 can handle the systems of equations pretty simply for you, but it takes a bit of practice to get good at entering things in properly and getting solutions.
I love you soo much I've been stuck on this thevenin problem with two voltage sources for ages.
Darryl,
You really saved me here. Thank you very very much!!!!!
"a supernode deserves to be in hot pink" lol made my day
Thank you! Very good explanation.
You saved my life.
very much thanks sir for your contribution
the best explanation i have ever seen
You sir are AWESOME....
thank you :D you help me a lot on this
I really wish you had explained how you came up with the last equation. It was a great video up until that point.
It's the equation for when you do nodal analysis for node 4, which he calls v4. He said that's what he was doing at 8:49.
I understand mang ….. piece of crap making crap video..... making zero sence @Dre
THANKS!!
THX a lot ! This helps me finish my assignment as the notes given by the lecturer are too hard to understand :(
wish I took you this semester instead prof morrell....
Obrigado, salvou a noite.
thanks for the video
What if theri is resistor next to 10V generator between node 2 and 3? Could it be solved with node analysis and is it practicle, do i just convert it to surent source? Or do i just use mesh analysis?
can you explain me where did you get the kcl equations?
Wait so at 3:00, does current leave from the - side or the + side of the voltage source between V2 and V3?
Thank you so much your help, can you Plz make videos about dependent current and voltage sources
The current out of node 4 through the 2k resistor from right to left is (v4-v3)/2k. The current out of node 4 through the 1k resistor from top to bottom is v4/1k. These two currents sum to zero. Doing some algebra gives the equation that I wrote for v4.
shouldn't it be (V3-V4)/2 cause the current direction is from left to right and current flows from higher voltage to lower voltage.
Or since we are solving for V4 we consider it to be at higher voltage??
I like your explanation of supernodes, but I generally think it's good practice to consider a node as a point where 3 or more elements are connected to it, this results in a lot less equations at the end of the day. So in your example, you would have node V2 and V3 only, and you would write that I1 = 5V/5K Ohms and for I4, you would write V3/(2K + 1K) Ohms.
why did you write (V2 - V1)/R1 if the current always flows from a higher to lower potential? It should be (V1 - V2)/R1 ? Why did you assume that V2 > V1 ?
Thank you Mr. Morrell !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! I think i just understood the protoboard !
@batgeo1982 My video "Voltage and Current Sources" talks about dependent sources beginning about 9:50. Several of my "Ad Hoc Analysis Example" videos also show how to do analysis with dependent sources.
thanx..
Thanks
Thanks
Question, when does the voltage become negative?
can we using only teo nodes??
thanks . Can you make videos about bode plots, transmission lines please?
Thanks
9:07 where did you acquire the formula from? i didnt get it
All he is doing is nodal analysis for the V4 node.
You get (V4 - V3)/2k + (v4 - 0 )/1k which is the same thing he got.
I was taught that current going in is positive and current going out is negative with respect to the node. But for the equation of the supernode everything positive even some current was leaving the supernode. I'm confused whether it makes a difference or not to have some current negative and some positive
what if there is a resistor parallel to that 10v?
Hello. What if there is a 3V instead of 10V? I think current doesn’t flow to first loop
I really don't understand why the currents at supernode are moving left at v2 and right at v3. In my textbook, the voltage source is set up the same way and the current at v2 is moving to the right. how do you know which direction the current is travelling here?
you assign it as you like
you can say that I one is going right and I2 going down
I will put those topics on the list of future videos. It will be a while before I get to them.
Say "Kirkoff" again, I dare you, I double dare you XD
i dont understand your jock
You could combine the two rightmost resistors which are in series, then combine this series combination that is in parallel with the 3kOhm resistor. However, you can't solve for most voltages or currents in the circuit this way because it contains two sources that are not in parallel or series with each other; nodal or mesh analysis or superposition are your popular options for solving it. The fact that the leftmost resistor is connected to both sources is why the voltage across it is so high.
why for node 4 cant i say v3-v4/2k, because in the super node we had a current, i4 leaving node3 going towards node4. which would be the higher (Vhigher - Vlower)/2k.
what is that program , the one you are typing in ?
Mahmoud Basyoni wolframalpha
how did you get the eqn for node 4 ??? explain...how? how did you assume the direction of current?
Current direction is always to the direction of voltage drop S M Tasnim Alam
S M Tasnim Alam
If it were me, I'd put the resistors together in series and get rid of V4 - strictly speaking, a node by definition is a junction in which 3 electrical components meet. Well in this case there is only two components so it is not a node.
would that make the last equation (V3-0)/3?
close it'll be (V3-0/3k)
At 3:38, how did you get V3 = V2 + 10v
The voltage drop across V2 and V3 is 10v. So it's actually V3-V2=10
Is anyone else not getting solutions when you plug into wolframalpha? I just get alternate forms and nothing else.
Did you ever figure this out?
Wouldn't I1 flow in the opposite direction and flow away from the 5V source?
Why are all the currents flowing out of the super node?
How would I enter this system of equations into my Ti-84 calculator?
Google might know
v1 is a node??
I dont get how you got the equation at node V4. Can someone explain?
Where did -V3/2000 come from? (at 9:03 of the video)
He went straight to the simplified ver coming out of:
((V4 - V3)/2k) + (V4 / 1k) =0
but with the direction of I4 the right equation should be (v3 - v4)/2k
What the original was (v3-v4)/2k = v4/1k if you simplify this you'll get his equation
Don't waste time trying to form an equation for V4. Once you have V3, V4 is just V3/3
That's because he skipped a step there that should have explained it.
This is a better approach using only 2 equations: (V2--5)/5 + (V2/4( + (V3/3) + (V3/3) = 0 AND (V2+10) = V3
u cant have nodes at bridges with less than three nodes?
V2 , V3 and reference nodes are enough to frame 2 equations to find out v2 and v3 .
I have not included solving the system of equations because there are many resources available to solve these systems. I do not know which resource students will use. You might look at khanacademy-he covers many different ways to solve the systems.
supernode is an easy way to go, i would have liked this guy to explain the nodes one by one, may it be harder, another circuit may not have such an easy setting, so i think this example is just unique not general
What if intead of an voltage source on the supernode, there was an current source?
in that case u will apply nodale directly
couldn't this be done with only two nodes?
why i1 IS OUT FROM V2
I thought you only use essential nodes in node voltage method...v1 is not an essential node therefore it can be ignored...
Exactly.
why not use only two nodal points instead of three you can combine 5V and 5ohm resistor use source transformation and convert it into an independent current source
Voltg source ko convert to kro cs me
I dont understand why you included the simple nodes in this example, where in the others you just used the essential nodes.
See my reply to CantCreat above.
Does current not flow from left to right "(v3-v4)/2k"
Why does this equation imply current flow from v4 back to v3.
Probably something simply but I am as confused as a chameleon in a bag of Skittles
that is too easy can u solve another one more complicated ???
yeah, just not an essential node (more than 2 elements connected).
I THINK U DIDNT NEED V1 AND V4
Thik se solve kro
i understood........... NOTHING. ._.
solutions are wrong
Fell asleep halfway.