Resistor network question Cant get it

[biochemguy]

Homework Statement

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

Homework Equations

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. anyone have any suggestions or maybe an easier way to approach the problem.

 

[gneill]

Homework Statement

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

Homework Equations

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. anyone have any suggestions or maybe an easier way to approach the problem.

Hi biochemguy, Welcome to Physics Forums.

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

 

[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)?

 

[gneill]

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)?

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)?

 

[biochemguy]

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

 

[gneill]

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

What is required for current to flow through a resistor?

 

[biochemguy]

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

 

[gneill]

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

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.

 

[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

 

[lazyaditya]

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.

 

[lazyaditya]

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.

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.

 

[gneill]

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.

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

 

[lazyaditya]

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

Thanx !

 

[lazyaditya]

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

 

[gneill]

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

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.

 

[lazyaditya]

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.

ok. Didn't knew that !