# [Urgent] Homework help (DC Circuits)

#### pmendz2010

Joined Mar 24, 2011
8
Hello guys! I have a homework in DC Circuits and I need to submit it tomorrow but I don't think I do not have much time if I do it alone since I still got a lot of homeworks to do for my major subjects. So if anyone can help me, I am willing to pay someone who can give me a step-by-step solution for this problem. I really need to get this done. Here's the problem:

Solve the voltages between each of the nodes (Va, Vb, Vc, and Vd) and ground in the figure shown.

(image attached)

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#### beenthere

Joined Apr 20, 2004
15,819

#### pmendz2010

Joined Mar 24, 2011
8

#### beenthere

Joined Apr 20, 2004
15,819
Our policy on homework starts with -
Important

The Homework Help Forum is not a free homework service; we are here to help your understanding, but fully expect the users of this forum to dictate the course of their own learning.

When posting a request for homework/coursework/assignment help, you must provide details of your attempts at the questions. Any thread that just posts up a copy of the questions without any attempts on the part of the opening poster will be directed to this thread and will be given 48 hours to satisfy the requirements detailed within. Help us, help you.
We must insist that you show work.

#### pmendz2010

Joined Mar 24, 2011
8
Our policy on homework starts with - We must insist that you show work.
Yep! I am fully aware of that and I did try solving the problems and I finished all of it except this one. I'm kinda new to DC Circuits and I am quite stuck in this one problem. Unfortunately, I think I am running out of time so I asked for help in this forum.

I am sorry if I am causing you trouble. Thanks for the help though.

#### pmendz2010

Joined Mar 24, 2011
8
R1 & 3 make a parallel circuit, as does R2 & 4. here is a link to solving for resistors in parallel - http://www.allaboutcircuits.com/vol_1/chpt_5/3.html

After that, it's a simple series circuit, which anyone can figure in a snap.
After combining R1 & R3, and R2 & R4, what am I supposed to do with the wire below R7 and R8?

#### beenthere

Joined Apr 20, 2004
15,819
Kinda looks like a 0 ohm resistor in parallel.

#### pmendz2010

Joined Mar 24, 2011
8
Kinda looks like a 0 ohm resistor in parallel.
I see. So the voltage there is also 0. Is it safe if I just neglect that wire and continue solving as if that wire isn't there?

#### beenthere

Joined Apr 20, 2004
15,819
As if those two resistors aren't present.

#### pmendz2010

Joined Mar 24, 2011
8
As if those two resistors aren't present.
Are you referring to R7 and R8? But how would I solve for the voltages between the nodes and the ground if those two resistors are neglected?

#### beenthere

Joined Apr 20, 2004
15,819
They are shorted by the wire. They have no effect.

#### Georacer

Joined Nov 25, 2009
5,182
beenthere are you sure the resistors R7 and R8 are to be neglected? The way I see it, the order of the simplifications is:

Ra=R1//R3
Rb=R2//R4
Rc=R5//Ra
Rd=R6//Rb
Re=Rc//Rd
Rf=R7//R8
Rtot=Rf+Re

Can you have another look?

#### beenthere

Joined Apr 20, 2004
15,819
Yes, I did not see the lack of a connector dot between R7, R8 and ground.

#### pmendz2010

Joined Mar 24, 2011
8
Yes, I did not see the lack of a connector dot between R7, R8 and ground.
Sorry but what does that mean?

#### beenthere

Joined Apr 20, 2004
15,819
It means that I walked into a trick school problem.

The resistor net is redrawn per the attachment. There is an interesting connection missing.

Note to self: never assume a school problem is supposed to represent anything in the real world.

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#### pmendz2010

Joined Mar 24, 2011
8
Sorry for the bother but I'm a bit confused with simple things and I need clarification.

Consider the image attached, what would be the value of V1 (voltage across R1)?

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#### Georacer

Joined Nov 25, 2009
5,182
Can any voltage be produced on the same node of a circuit?
The two ends of the resistor are essentially the same point in the circuit, and voltage is defined as the difference of potential energy between two points of the circuit.