# Resistor network question Cant get it

1. Feb 12, 2012

### biochemguy

1. The problem statement, all variables and given/known data
A network of 5 resistors is constructed to a 12.0V emf. the total current in the circuit is 12.0A. determine, draw and label the configuration for the network of resistors
R1=1ohm, R2=1ohm, R3=1ohm, R4=1ohm, R5=4ohm

2. Relevant equations

3. The attempt at a solution
i figured that the overall resistance must be 1Ohm using Ohm's Law but I've filled up like 2 pages with stuff that doesn't add up. any one have any suggestions or maybe an easier way to approach the problem.
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Feb 12, 2012

### Staff: Mentor

Hi biochemguy, Welcome to Physics Forums.

Could you solve the problem if there were only 4 resistors?

3. Feb 12, 2012

### biochemguy

we have to use all 5. it would be way easier if i didn't have the 4-ohm resistor. that's the one that is throwing a monkey wrench in my attempts. if i had 2 pairs of the 1 ohm resistors in parallel that would give me the 1-ohm right? (1/2+1/2)?

4. Feb 12, 2012

### Staff: Mentor

Right. So the question is, is there a configuration of the four 1 Ω resistors that gives you the required 1 Ω total, but which provides a couple of nodes where you could attach the 4 Ω resistor where it would not make any difference (it would not conduct any current)?

5. Feb 12, 2012

### biochemguy

not quite sure what you mean. how could you make it not conduct any current?

6. Feb 12, 2012

### Staff: Mentor

What is required for current to flow through a resistor?

7. Feb 12, 2012

### biochemguy

Voltage? sorry if i'm not up to speed, its just physics is definitely not my forte.

8. Feb 12, 2012

### Staff: Mentor

Yes, a potential difference across the resistor is required. So if you can lay out the other four resistors in such a way that two nodes happen to have the same potential, anything connected across those two nodes will have the same potential -- so no potential difference.

9. Feb 13, 2012

### biochemguy

thanks gneill. i ended up figuring it out in the library this morning. I think he just wanted it in a single loop, but you seem to know way more than me so hopefully you can help when i have more question.
thanks again though

10. Feb 16, 2012

put 3 1 ohm resistors in parallel to each other then connect a single 1 ohm resistor in series with the previous combination. Then connect the last 4 ohm resistor in parallel to the whole combination, the resulting circuit will give you resistance equivalent to 1 ohm.

Thus the circuit applied to 12 volt source will give 12 ampere current through circuit.

11. Feb 16, 2012

Its a very good approach that you have posted over here, it would be of help to me if you can post a method or a diagram that how would you arrange these nodes and resistance in such order.

12. Feb 16, 2012

### Staff: Mentor

Think of a balanced bridge circuit. No current flows through the bridge.

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13. Feb 16, 2012

Thanx !

14. Feb 16, 2012

Can you solve this problem plzz ! I am getting answer -5 volts !

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15. Feb 16, 2012

### Staff: Mentor

New problems should be posted in their own, new threads. Also, you must show your own work/reasoning before we can know how to help you.

16. Feb 16, 2012