Thevenin Equivalence

[Hacp]

Find the Vth of this:

I think this is the answer but I don't know why.

 

[Leros]

Do your own homework?

 

[PottedMeat]

fuck no.

 

[Hacp]

Do your own homework?

Sept have the answer but I don't know why.

 

[Leros]

Sept have the answer but I don't know why.

The answer wasn't there when I made that post. You added that afterward.

 

[JohnCU]

id help but i cant see the pics, bbzzzdd is blocked at work

 

[jman19]

Sept have the answer but I don't know why.

Do your own homework? ATOT isn't here to give you a free ride through college.

 

[Tim]

All of the people who just chime in with "Do you own homework" only do so because they have no idea what they're even looking at.

That being said, do your own homework.

 

[Juncar]

Find the Vth of this:

Are those Ems supposed to be batteries?

 

[ss284]

Voltage sources.

 

[Gibson486]

you have to put them it terms of current and then simplify it.

That said, Thevenin Equivalents are the devil. They are easy until some tells you to specifically do it.

 

[Hacp]

It isn't even Hw, Just review for an exam. it hasn't been taught, just assumed that we know this shift. . No info in the textbook on how to do it

=O.
Maybe that's how you do it.

 

[Gibson486]

The point of Thevenin Equivalence is that you can always make an equivalent circuit with a different source to simplify it. It's useful because you do not have to know anything else about the circuit to solve it. In reality, no one really uses it because there are easier methods to do it.

One useful thing you can get out of it is current vs voltage sources. Under Thevenin, Voltage sources with a resistor series is the same as a current source and that same resistor in parallel. In order for this to be valid, however, you have to assume that the current source only goes through one brach of current, otherwise, it becomes invalid. As a result, using Thevenin with multiple branches becomes tedious (you have to do a thevenin for each branch). Now you can see why no one in the industry uses this method anymore.

So, why do you learn it? Well, you already know it, you just do not know you know it. All Thevenin and Norton Equivalents are is just simplifying a circuit in terms of a specialized manner. When you have a circuit with two sources, yeah, this could be used. You solve both sides of the circuit, then add them.

 

[frostedflakes]

Have you guys learned about nodal analysis? There are a handful of ways to solve Thevenin equivalents (mesh analysis, linear superposition, etc.), but that's probably the easiest for this circuit. Just write the node equations (or in this case, there would only be one), and once you have that it's just algebra, solve for the V term.

You're on the right track with that ^, just set it to 0 and that's the KCL equation for the bottom node. Then you solve for V.

 

[Gibson486]

It isn't even Hw, Just review for an exam. it hasn't been taught, just assumed that we know this shift. . No info in the textbook on how to do it

=O.
Maybe that's how you do it.

your track equals correct. Keep going!

Oh, and you are solving it using nodal analysis, which in turn, you are doing thevenin without even knowing it. Essentially, you do each branch separately, then add them, which is what nodal analysis gives you right off the bat. No superposition needed (well, you are superimposing, just not by steps)

 

[Hacp]

Have you guys learned about nodal analysis? There are a handful of ways to solve Thevenin equivalents (mesh analysis, linear superposition, etc.), but that's probably the easiest for this circuit. Just write the node equations (or in this case, there would only be one), and once you have that it's just algebra, solve for the V term.

You're on the right track with that ^, just set it to 0 and that's the KCL equation for the bottom node. Then you solve for V.

This Isn't an EE course

 

[frostedflakes]

Well even if it's a physics course or something like that, the professor should have taught you guys some of the basic tools for circuit analysis if he's asking about Thevenin equivalents. Unless you have a really shitty professor.

Anyway, just Wikipedia nodal analysis, it's pretty straightforward.

 

[Gibson486]

Well even if it's a physics course or something like that, the professor should have taught you guys some of the basic tools for circuit analysis if he's asking about Thevenin equivalents. Unless you have a really shitty professor.

Anyway, just Wikipedia nodal analysis, it's pretty straightforward.

judging by his equation, he already knows nodal analysis....he probably does not know it by name.

 

[us3rnotfound]

judging by his equation, he already knows nodal analysis....he probably does not know it by name.

This is the story of my struggles and triumphs with the major of EE. I'm halfway through senior year, and I'm just realizing that maybe most of the professors I've had are just not that good at teaching.

 

[Gibson486]

This is the story of my struggles and triumphs with the major of EE. I'm halfway through senior year, and I'm just realizing that maybe most of the professors I've had are just not that good at teaching.

you are not alone...I did not realize what I knew until I was taking the FE exam 1 year after I graduated. Infact, I did not realize the point of Thevenin Norton until 2 years after graduating and I do not even work in the field anymore.