# Thevenin's theorem on the following equation

Discussion in 'Homework Help' started by Cameron Fife, Nov 2, 2014.

1. ### Cameron Fife Thread Starter New Member

Nov 1, 2014
18
0
Hey guys, I'm nervous about answering this equation using Thevenin's theorem. Usually the load resistance is in the middle of circuit, but in this one, one of the two voltage sources is also in the middle. I'm really unsure what I should do, I'm trying to find voltage across R1 and I assumed the rightmost pathway could be a load and got .725 V.

EDIT: Whoops, I meant *following problem* with the title

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2. ### mjakov New Member

Feb 13, 2014
20
5
Hi, have you thought about simplifying the circuit first? Resistors R1 and R3 as well as R4 and R5 are in series. Then you could use the node voltage method to calculate the voltage at point A between R3, R2 and R4. Calculating voltage at R1 would then be a simple matter of a voltage divider between Vs1 and Va.

3. ### shteii01 AAC Fanatic!

Feb 19, 2010
3,297
482
Step 1.
Remove the resistor.

Step 2.
Replace all independent voltage sources with shorts.

Step 3.
Find the equivalent resistance of the circuit.

Step 4.
The equivalent resistance of the circuit that you found in Step 3 is Thevenin Resistance.

All you have to do now is find Thevenin voltage source.

4. ### WBahn Moderator

Mar 31, 2012
17,454
4,701
It doesn't matter where the "load" is located or what is around it. You seem to be trying to learn a bunch of rote techniques based on specific circuit topologies instead of learning the concepts involved.

You have a circuit. That circuit contains a subcircuit consisting of one or more components that connects to the rest of the circuit at two points. Draw a box around the components in the subcircuit and call that your load. Remove those components leaving you with two interface nodes. What is left is the part of the circuit that you are trying to find the Thevenin equivalent for. Analyze the circuit to find the voltage between the two interface nodes. That is the Thevenin equivalent voltage. Turn off all of the independent sources in the circuit and analyze it to find the resistance between the two interface nodes. That is the equivalent resistance. If you have dependent sources, things are a bit more involved, but you are not at that point yet so don't worry about it.

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