Super position principle

Thread Starter

nguyengiathinh

Joined Jul 4, 2022
14

I use source transformation in the right of the picture to get Vr but when I use superposition I get a other answer. plz explain to me

Ya’akov

Joined Jan 27, 2019
7,026
Is this schoolwork?

Thread Starter

nguyengiathinh

Joined Jul 4, 2022
14
Is this schoolwork?
I am a student at university sir. Just I want to know clearly about the superposition principle.

Ya’akov

Joined Jan 27, 2019
7,026
I am a student at university sir. Just I want to know clearly about the superposition principle.
There are rules concerning how members are allowed to help with required schoolwork. If this is something you are supposed to know for a course then it needs to be in the “Homework Help” forum to make that clear.

WBahn

Joined Mar 31, 2012
28,177
MOD NOTE: Moved to Homework Help.

WBahn

Joined Mar 31, 2012
28,177
View attachment 280326
I use source transformation in the right of the picture to get Vr but when I use superposition I get a other answer. plz explain to me
Your work, what little of it is presented, is very messy and hard to follow. Do yourself a big favor and get in the habit of making the effort to be very neat and clear in your work -- you will see your grades go up markedly, both because you will make fewer mistakes and catch more of the ones you do make, and because the people grading your work will be much more predisposed to look favorably on it.

It looks like your basic problem is that you are doing something that your textbook/teacher should have been very clear that you can't do. You are doing a source transformation and then expecting the transformed components to somehow be relevant to the original ones. They aren't.

When you do a source transformation, you are essentially drawing a black box around a portion of the circuit and saying that you can replace that black box with a block box containing a different set of components and the rest of the circuit (i.e., the circuit NOT in the box) won't be able to tell the difference because the behavior of the circuit's in both boxes are identical AT THE POINTS where the black box connects to the rest of the circuit. There is NO claim that what happens INSIDE one of the black boxes has ANY relation to what happens inside the other black box EXCEPT at the boundary where it interfaces to the rest of the circuit.

So if you want to know the voltage across a particular resistor, you cannot perform any source transformation that involves that resistor -- it must remain part of the circuit NOT in the black box.

Last edited:
Similar threads