# Calculating thevenin

1. Jul 14, 2006

### esmeco

I was wondering,how do we calculate the thevenin resistance in a circuit with a load resistor?Do we remove the load?How do we calculate the voltage Lat the load terminals.Like for example in this circuit:

http://i75.photobucket.com/albums/i281/esmeco/superpositionandthevenin.jpg [Broken]

I'm a bit confused now...

Last edited by a moderator: May 2, 2017
2. Jul 14, 2006

### esmeco

Can anyone help me?

3. Jul 14, 2006

### FrogPad

What book are you using?

4. Jul 14, 2006

### esmeco

Actually I'm not using a book...If you're referring to those exercises,they're practice exams...ANd for guidance I'm using a book in a language which isn't english...But I'm really confused because I've heard my colleagues saying that you don't necessarily remove the load resistor to find the thevenin at the load terminals,but on the Internet they all say you have to remove the load resistor inorder to find thevenin voltage...In this case,if we remove the load resistor I'm not sure on how we calculate the voltage at those terminals...

5. Jul 14, 2006

### FrogPad

Go through the video examples on this website,
http://bcs.wiley.com/he-bcs/Books?action=resource&bcsId=2149&itemId=0471487287&resourceId=5675

I think it will help you out more.

As far as Thevinin's goes, you:

1) Remove the load.
2) Find the voltage accross the terminals of the removed load $V_{th}$
3) Find the Thevenin equivalent resistance at those terminals $R_{th}$

If only independent sources,
short voltages
open currents

If only dependent or both dependendent and independent it differs.
I'll type up how to do it, if you need it.

4) Connect the removed load up to your new equivalent circuit,

Vth----Rth----(+)
|
|
|-------------(-)

Load connects to (+), and (-) terminal

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