Finding equivalent resistance of four resistors in series and parallel

[Atlos]

Homework Statement

I'm just trying to find the equivalent resistance of this:
http://sogacity.com/images/circuit.png

Homework Equations

Resistors in series add and resistors in parallel inversely add.

The Attempt at a Solution

I'm not even sure how to approach this. I guess I can't get my head around how it is set up. R1 and R2 are in series, but being connected to R3 and R4 in multiple places is what's confusing me. If somebody could help me create an equation for the equivalent resistance of all of that I would be thankful.

 

[vk6kro]

Follow the path from the power source around the outside of the drawing. No resistors.

 

[Atlos]

Do you mean like this?

http://sogacity.com/images/circuit2.png

So would R1 and R2 be in parallel with R3 and R4? Like (R1 + R2)||(R3 + R4)?

 

[vk6kro]

Because there is a continuous path around the resistors, they are shorted out and have no effect. So, the resistance is zero.

 

[Atlos]

Ah I understand it now, not sure how I missed that. Thanks!

 

[Atlos]

Uggh, I knew it couldn't be that easy! I drew a wire where there shouldn't have been one. This is the real circuit:

http://sogacity.com/images/circuit3.png

Anyways, I still have no idea how to approach this problem. Would it be (R1||R4)+(R2||R3) since R1 and R2 seem to be in series and R1R4 and R2R3 look to be in parallel?

 

[vk6kro]

It looks like they touch at the centre point.

So, yes, the top two are in parallel and the bottom two are in parallel and then the two parallel parts are in series.

It might look more familiar like this:

[PLAIN]http://dl.dropbox.com/u/4222062/series%20parallel.PNG

 

[Atlos]

Awesome, thanks a lot.