Electrical Engineering: Ch 4: Circuit Theorems (16 of 35) Thevenin's Theorem Ex. 1
ฝัง
- เผยแพร่เมื่อ 29 ก.พ. 2016
- Visit ilectureonline.com for more math and science lectures!
In this video I will find i=? of a load resistor by converting a linear circuit with 1-voltage and 1-current source to a Thevenin's circuit.
Next video in this series can be seen at:
• Electrical Engineering...
I am actually skipping class to see this video, to reduce the time needed for understanding and practicing the concept from +2 hours to 30 minutes. Once again a well made, carefully thought out tutorial by my favourite online professor! Keep up the great work, the world needs more engineers!
im IN class watching this video. Learning far faster then if i was paying attention lmao
How'd you end up doing in your class? (your grade=?)
couldnt have put it better myself :D ++++
the world doesn't need more engineers. wait till you get out and can't get a job or gotta work for $15 for a greedy PE. I remember how optimistic i was b4 I graduated
@@chrisvincent782the world always needs engineers. The seniors aren’t gonna be here forever
This guy is the most underrated professor of all times!!!
He should be getting millions and millions of views because of the way he teaches!
Thank you
It is definitely 😊
Wow, this is the first video I've seen by you, and in eight and a half minutes I learned more about Thevenin circuit analysis than I have in the past week and a half in my circuits class. You are a god-send! Thank You!
This is what I like, straight to the point and consistent. I wish my professor wouldn't side track every so often during lecture. May a statue be erected for your work.
I am starting to fall in love with you !! Even the tutor I paid didn't teach so well.
Thank you. Glad you like our videos.
Sir you’re the best teacher I ve ever watched
We appreciate the feedback. Glad you found our videos. 🙂
@@MichelvanBiezen i was studying circuit theory retakes and the way you solve is almost the same as our teacher. And I understand much easier here. Thanks again
Great!
THE BEST TEACHER EVER! I wish you are my teacher. From Philippines btw thank you I love your tutorial videos sir!
thank you, Michel ! I watched other videos about it and didn't find such a clear explanation as yours
Hi Sir
Did you remove R(load) because you want to get an open circuit and hence it would be equal to infinity? And what are the differences between R(load) and the other resistances. Finally, where did you assume is the ground?
Thanks
best video out there about thevenin voltage! finally understand this !!!!!
I’m really don’t know how to thanks you I was not know anything in this subject but after I watch your video i understand to you thank you 🙏🏼.
Glad we could help!
Sir can we use current divider to find the thevnin voltage ?
Geez... you just helped me understand 6 hrs of lecture in 8 minutes 😯👍
Glad we could help!
Thank you - this really helped me understand!
Thank you for explaining this. Your method of teaching is really nice.
can't i use source transformation to change the current source into another voltage source?
very clear, state the rules, act according to the rules, you get the result. thank you
To find thevinin resistance both independent and dependent source must be removed or only independent source should be removed?
I’m in my first year of mecanical engineering. My professor is a nuclear engineer (patents in multiple things, rich as fuck 🙄) so he teaches DC as a way to pass his time.
He doesn’t give the slightest fuck about us, but this video finally made me understand it! Thank you sir! It’s not as hard as it looks.
I love your videos! Greetings from Belgium 🇧🇪
Im curious....How many degrees do you have? You literally teach all my uni courses! :)
And Michel van Biezen
teaches them better than average professors in the best universities!
If you are smart enough you can teach anything. You teach yourself and then you teach it to others. Once you teach others it becomes easy to keep the information you learned.
@@MA-qz1sd couldn't agree more with you ;)
He even looks like Euler, definitely his reincarnation.
To be honest, an engineering curriculum covers most of his channel.
Hello sir Can you apply the current and voltage in this case Thank you
You sir, are amazing. Thank you so much you have helped me a lot
Under this concept I think every problem will be Easy to solve....thanks you so much Sir💪💪
You are saving me through circuits sir
Very nice! Thank you Pr. Van Biezen
Very good. Thank you! Just a little lost why VTH = V at open terminals.
what does short voltage source mean?
Very thorough explanation. I finally get the concept. Two question: 1 - I assume, in a practical sense, that once you solve for the Thevenin's equation, one can replace the RL with any value and the resulting current will hold true to the original model. 2 - Is there a good source of practice problems, with answers, to continuing sharpening my new skill?
sir how i increase knowledge in network theorem..?plz tell me
why ist 1 ohm is in paralell? generally, how to know resistor is in parallel or series, when it's open circuit like in 2:12 ?
I appreciate your help. I now learned. you look like e good prof. from now on I'm gonna watch your videos when I have something in my mind
Glad to help
Thank you Prof. Michel! Again.. :)
Brilliant stuff this.. now my tiny brain gets it! Thanks!
Dear Professor,
Are we looking the circuit from the right when we shorted the voltage and cut off the current source to find the R thevenin ? because i do not know why the 1ohm resistance is not remooved or we do consider it when finding the Rth ?
We are always looking at the circuit from the perspective of the "load" or load resistor.
Thank you. It was a great explanation.
thankyou so much :D this has been really helpful to me
Dear Professor,
Thank you so much for your help. I am having trouble understanding why Vth at the node and across the terminal is similar. It would be really helpful if you can explain. Thank you so much for your time.
Best,
Iftikhar Khan
+Iftikhar A khan
When finding the Vth, the circuit between A and B is open, which means there is no current between Vth and A and thus there is no voltage rise or drop across that 1 ohm resistor.
Thanks Sir 😊
Rth=(4//12)+1=4
Eth=(32*(12/4+12))+(2*(12/(4+12))*4=24+6=30v(Superposition theorem)
And then i=30/(4+5)=30/9A
4:32, the why is the voltage from the node equal to the voltage to the right of the 1-ohm resistor? Isn't there a voltage drop because of that resistor?
Edit: nevermind didn't listen carefully enough, that part of the circuit is shorted so no current so same voltage through that line. I'll keep this comment up in case anyone else was confused.
There can only be a voltage drop if there is a current through the 1 ohm resistor, and in this case there is not.
Hi sir,
I have one doubt. vth is the voltage across the terminals A and B. In Equivalent circuit we connect the resistor series to the vth. in equivalent circuit the voltage across the terminals A and B is not equal to Vth because some voltage drop present across the Rth . so in equivalent circuit the voltage value across the A and B is not equal to vth. am I right or wrong sir .Please clarify my doubt sir.
Thanks in advance:)
All the other vidéos and my teacher failed to make me understand.
But now I get it ! Thank you !
Happy to help!
Dear Mr. van Biezen,
What are the main advantages of using the Thevenin's Theorem over source transformations to answer the example you illustrate in your video ?
Thank you.
Ultimately it comes down to what you prefer. Here we are just showing the different methods so you can become familiar with them.
Thank you for this tutorial
thank you so much, it’s really helpful.
I so love your page 😍.
That is great to read.
Why is the Rth(4ohm) different with RL(5ohm)
Thanks so much! Love from Sweden ❤
Thank you. Welcome to the channel! 🙂
This might be an obvious question but lets say I don't have a current source in a branch but instead I am given that 'A 'amp of current flows, then would the source transformation still work? ( IT should I suppose, but I could be wrong, I am a student of class 12th and electrical circuit problems are my weakness)
I would try Kirchhoff's rules.
Best video on Thevenin's Theorem
Thank you. Glad you found it helpful. 🙂
Why u multiply 12 in node analysis
Dear professor, thank you for the video! One question though, why is Vth at the node equal to Vth at the open cable?? What about the "node"(dunno what else to call it), right above the current source?
Because there is no current flowing through the 1 ohm resistor and there is no resistor between the node and the 1 ohm resistor (no voltage drop).
Dear sir,
Could you tell me how can i find the RL using by thevenin's theorem. ??
The load resistor is not "found" but should be a given in the problem.
If in an example we have dependent current and voltage sources ( we must short these type of voltages ?)
Current sources are removed and left open and voltage sources are replaced with a short.
You are doing the lords work
Thank you. I like to think that both my wife and I are of service doing this work.
@@MichelvanBiezen I sincerely thank both of you
could someone please explain to me,why there is no current flow to that end where 1-ohm resistance is at. I did search some but still don't really get it. I know that it is an open circuit. but the current does not flow toward that end at all tho?
Any branch that does not form a complete closed loop will have zero current flow.
Michel van Biezen thank you so much sir
👌
Sir, can u plz explain me that, how did u take voltage at the node as Vth? thank u Sir
Since there is no current through the 1 ohm resistor, there is no voltage drop between the node and the point to the right of the 1 ohm resistor. Thus the node must be at the same potential as Vth
Tnk u Sir. I got it.
Awesome video sir! Thank you!
Looks like you are going through the whole playlist! 🙂
Hello there just wondering if we can use Voltage divider to determine the Vthevenin?
Thanks for your response.
The voltage divider should work in almost every case.
Thank you sir !
Thank you so much Professor for your explanation. It would be extremely helpful if you can show an example with a dependent voltage or current source. Thank you so much!
+Iftikhar A khan
Good point. I'll have to add a few examples with dependent sources.
It helped a lot thanks!!!!
Glad it helped!
What it both voltage and current source are at the edge of the circuit and the load is in the middle of the circuit???
Then I suggest you redraw the circuit such that the load is at the edge.
Since the 1 ohm resistor is good as nothing, how about we simply use the voltage division rule between the 12 & 4 ohm resistor to find Vth?
It is better to learn the technique so you can learn to do more complex problems.
Hello Professor, I'm slightly confused why the node we were solving is V_TH, how does that node equal the voltage across the gap?
If there is no current flow (due to the gap) then there is no voltage drop and the node voltage must equal the V_TH
why is no current flows in 1ohm ?
Unless that circuit is connected no current can flow through the part of the circuit that is not a complete loop.
Sir, how can we determine whether this circuit linear or not ?
i believe this means that it's a circuit with no wires moving above/under each other. where in the figure it would look like a little bump.
sir thank you so much
Hi professor, why did you does the voltage through the 4ohm resistor = 32 - Vth ?
Using Ohm's law: I = V/R to find I1 we need to find the current through the 4 Ohm resistor. The voltage drop = 32 V - V at the node (V at the node in this case = Vth)
🙏🙏🙏
👌👌👌
👍👍👍
Thank you very much Sir!!!
Sir, how can I know that the Voltage drop is (32-Vth)/4 but not (Vth-32)/4?
We are making the assumption that 32V is a higher potential than Vth because we assume the direction of I1 is from left to right in the circuit.
@@MichelvanBiezen yep, my professor just assumes current is leaving so the node we're dealing with always appears first in the calculation of voltage dropped.
Sir can I use superposition theorem to fiend Vth
Usually, multiple methods will work on the same circuit. We show the different methods, but ultimately, you will use the one you like the most.
Why is there no current running through the 1-ohm resistor? I thought the 2 Amps will travel throughout or is it because of the resistance on the left side of the circuit much greater than the right that it's negligible?
In order to have a current, you must have a closed circuit. With the load resistor removed, the current has no place to go, so you can't have any current through the 1 ohm resistor.
@@MichelvanBiezen Oh man thank you so much , now I see how silly my question was.
Not silly at all. Sometimes these types of things really trip us up and it helps to get it clarified.
My teacher needs to watch your videos
This is so good
Dear Professor,
I am having trouble figuring out why the 4 and the 12-ohm resistor is in parallel, shouldn't the be in series ? Can you please explain? Thank you!
When the current source is removed and the load resistor is removed, then there is only one current path and the 4 and 12 ohm resistor are then in series.
Now, you're saying that the 4 and 12 ohm resistor are in series but in the video you say they are in parallel.
Ah, now I understand you question. When finding the Thevenin resistance, you have to calculate the resistance relative to the terminals at the removed load resistor, and in THAT case the two resistors are in parallel.
thank you ! now i get it
Sir why do you also said that current is not flowing in the 1ohm resistor?
When using Kirchhoff's law to find Vth, why do we not say (Vth - 32)/12? As far as I understand, its always the difference of the two nodes on either side of the resistor, divided by the resistance, and the 12 ohm resistor is also connected to the 32V and Vth.
You must always express everything in terms of an equation, and since (Vth - 32)/12 is not an equation, I cannot answer your question.
Good day Mr van Biezen, I would like to ask how do you know that the voltage is the same between the two nodes?
Not sure which 2 nodes you are referring to, but if it is the two nodes at the top, there is no component between the two nodes, therefore there cannot be a voltage drop and there is no current througn the 1 ohm resistor so there is no voltage drop there either.
@@MichelvanBiezen thanks Sir
i can not find the series and paralal connection properly.can you help me to solve the problem dear professor?if you make a class lecture on this topic then it may be very helpful for myself.
You can find some videos here: PHYSICS 41.1 RESISTORS IN PARALLEL BRANCHES
Thank you very much..sir
a 230V 50hz ac supply is connected to a resistance 2.5ohm coil of inductance 0.06h and capacitor of 6.8uF connected in series. calculate
impedance of circuit
current
phase difference between voltage & current
We have a lot of example just like that in this playlist: PHYSICS 49 RCL CIRCUITS
Thank you. Very usefull
You are welcome. 🙂
How do I know where the load resistor is? if it isn't stated in the circuit?
The "load resistor" is a placeholder for any portion of a circuit that is attached to a pair of terminals. The "load resistor" can be a resitor - inductor or resister - capacitor, or resistor - capacitor - inductor combination or an entire portion of a circuit. For example exercises like this the location of the load resistor must be indicated, otherwise there would not be any way of knowing where it is placed.
Thank you very much sir,
I am student from India
Our electrical lecturer isn't able to explain this us properly.Your explanation is very amazing.....
Welcome to the channel! We are glad you found us. 🙂
Be patient when learning. Nobody is perfect.
Here is my video th-cam.com/video/Rqpiz6_3OUw/w-d-xo.html
my good teacher iam from ethiopia
Welcome to the channel! 🙂
please which text do you recommend for circuit analysis. you're such a great teacher
We can't really endorse any texts. There are many good ones available.
Good day Professor
Why does current not go through the 1 ohm resistor
Because it is an open circuit at the end A. Because current needs a closed path, current does not flow in the direction of A and therefore does not flow through the 1ohm resistor.
Why are 4ohms and 12ohms in parallel but in the equivalent circuit 4 and 5 are in series, when to me at least they have the same configuration?
Since the current moving from left to right through the 4 ohm resistor does not have to go through the 12 ohm resistor, but can also go through another branch, they are therefore not in series. In the equivalent circuit ALL of the current flowing through the 4 ohm resistor MUST also flow through the 5 ohm resistor (there is no alternative path) and therefore they are in series.
Shouldn't you add the 4 and 1 in series and then calculate with the 12 in parallel? Would that be incorrect.
That would be incorrect. Try it and see if you get the same answer.
Michel van Biezen Different results, however I saw some videos doing that way, I'm not sure why, and others doing your way too.
Dear Sir, how do you determine the direction of the current flow of I1? why is it clockwise instead of anticlockwise?
Sometimes it is obvious as the (conventional) current flows from the positive terminal to the negative terminal. It can also be determined using Kirchhoff's rules. And if you are not sure, you can "assume" a direction. If the direction is wrong, you'll end up with negative answers for the current thus it doesn't matter, your answer will then tell you the correct direction
@@MichelvanBiezen Thank you very much for your reply
How do you know if the resistances are in series or parallel please?
If the current (going from A to B) must go through both resistors, then they are in series. But when the current goes from A to B and has a choice to go through one or the other, they are in parallel.
Many thanks, Professor!!
How vth is voltage across that node
th-cam.com/video/w7a88ODjdV4/w-d-xo.html
thank you
Sir i was trying this question in a different way. I followed the steps for example but rather than doing nodal analysis I used source transformations to simplify the circuit. However I didn't manage to get to a final answer. Could you try this question using source transformation pls and get back to me? Because i believe this method should work too.
Yes, source transformation should work. Most of these circuit problems can be solved using any of the methods presented. (some are more easily solved with one method versus another). That said, it is very easy to make a single mistake somewhere which will throw off your final answer.
Hi, how you get 5 in RL?
RL is the load resistor. That must be a given value. If the load resistance isn't given you cannot solve the problem.
So why no current flow through the 1-ohm resistor?
Once the load resistor is removed (RL), the brach now has an open and current can only flow if there is a continuous circuit.
Question: on using kvl for solving for the current across the first mesh, the vth turns out to be 36v. Please could you help me with an explanation or perhaps a correction for this paradox. Thank you so much for all you've explained. You have really assisted me in my academics.
I didn't quite follow your question. Are you saying the if you take the original circuit and solve for the voltage across the load resistor, you find it to be 36 V and you wonder why it doesn't equal the V th? They are not supposed to be the same since the V th is found without the load resistor.
@@MichelvanBiezen No sir. I followed all your steps prior to when you used the nodal analysis, in which place i used kvl. The answer then varied
It is easy to make a little mistake anywhere during the solution of the problem. (I do that too often myself). If no mistakes were made, the solution should be the same.
Thank you sir, I'll need to brush up on elementary math then.... lol 😅
Professor, how do we determine the directions of I1, I2 and I3?
You take a guess, and then work with those guesses. if you guessed wrong, you'll get a negative answer for the current.
@@MichelvanBiezen my professor for node voltage analysis tells us to assume all currents are leaving an essential node and to treat leaving as positive and vice versa for entering
Plz make video on theory 😞
Great treatment of this confusing topic! 😅
Glad you liked it. 🙂
BTW you have a Belgian/dutch name? Bij toeval afkomstig van deze contreien? 🤔
Ik was geboren in een klein dorpje in de gebuurte van Antwerpen.
Thank you for making this video, it saved my arse from getting F for my test
i wonder teacher if we can use mesh analysis in this circuite the answer will be the same ?
No matter what technique you use, the answer should always be the same. We show a lot of different techniques, but essentially any technique that works will do.