Thevenin Equal Resistance - Strange Circuit

[staggarhs]

Homework Statement

I want to find Rτ (Thevenin Equal Resistance) if the load is R4 in the attached image's circuit.
As easy it may seem, I get confused because it asks for the equal resistance between A and B.

Homework Equations

The Attempt at a Solution

We remove the voltage sources and s/c them. Then we have: R1 is parallel to (R2+R3) -> R1//(R2+R3).
R5 parallel to the rest. So we have in total: Rτ= [R1//(R2+R3)] // R5

 

[Redbelly98]

Welcome to PF

I see no current sources in the figure, those are voltage sources. So, what do we do with voltage sources?

Also, note R2 & R3 are not actually in series. Because node A has a path leading to R4, they (R2 & R3) do not have an equal current going through them.

 

[staggarhs]

Sorry my mistake. I meant Voltage sources. I need to find the Thevenin Equivalent Resistance if i take R4 as the load. So I replace voltage sources with short-circuit and also remove the load R4. From this point could you help me figure out the connections of the resistors ?

Thanks again...

 

[Kruum]

Your approach looks ok. But the calculations are wrong. Check again how to calculate the paralleled resistances. Have you gotten E_T already?

 

[staggarhs]

Your approach looks ok. But the calculations are wrong. Check again how to calculate the paralleled resistances. Have you gotten E_T already?

I haven't done any calculations yet, I just indicated how I think the resistors are connected. No I just want to find R_T

 

[Kruum]

I haven't done any calculations yet, I just indicated how I think the resistors are connected. No I just want to find R_T

Oh, okay. I thought those //'s were division marks.

 

[Redbelly98]

Sorry my mistake. I meant Voltage sources. I need to find the Thevenin Equivalent Resistance if i take R4 as the load. So I replace voltage sources with short-circuit and also remove the load R4. From this point could you help me figure out the connections of the resistors ?

Thanks again...

I would redraw the figure (with voltage sources shorted), with "A" at the very top and "B" at the bottom. Redraw/move the resistors around until you see some that are in parallel or series, and combine them.

 

[staggarhs]

I would redraw the figure (with voltage sources shorted), with "A" at the very top and "B" at the bottom. Redraw/move the resistors around until you see some that are in parallel or series, and combine them.

I came up with this one, but the equivalent is different than the first one i posted ( Rτ= [R1//(R2+R3)] // R5 )

In this case it is: R_Τ=[(R₁+R₂)//R₃ + R₅]

Please give me any hint as I am very confused.
Thanks a lot

 

[Kruum]

Please give me any hint as I am very confused.
Thanks a lot

I'm not sure if this is any help to you, but what can be said about any open circuit (i.e. unconnected wires)?

 

[Redbelly98]

I came up with this one, but the equivalent is different than the first one i posted ( Rτ= [R1//(R2+R3)] // R5 )

In this case it is: R_Τ=[(R₁+R₂)//R₃ + R₅]

Please give me any hint as I am very confused.
Thanks a lot

There's some problems with your figure. Just for example, R2 should connect between A & B, after Vs2 is shorted.