# Total resistance.. Is my answer correct?

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#1
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3 months ago
#2
(Original post by sarah630)
It would help if you could post the original question.
The diagram is a bit ambiguous without a cell or some indication of how the current is meant to flow.
For example, are the resistors supposed to be in parallel groups?
If you have made this question up yourself, I suggest abandoning it and using real questions from a book or past papers.

In short - you cannot solve that circuit question as it stands.

By the way - if the resistors are meant to be in parallel groups, then you have combined them incorrectly.
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#3
(Original post by Stonebridge)
It would help if you could post the original question.
The diagram is a bit ambiguous without a cell or some indication of how the current is meant to flow.
For example, are the resistors supposed to be in parallel groups?
If you have made this question up yourself, I suggest abandoning it and using real questions from a book or past papers.

In short - you cannot solve that circuit question as it stands.

By the way - if the resistors are meant to be in parallel groups, then you have combined them incorrectly.
Here is the original question. I'm supposed to find the current I6 using Thevenin's theorem. So I did the first step of removing the Load resistor, short circuiting the voltage sources and calculating the equivalent resistance.
0
3 months ago
#4
(Original post by sarah630)
Here is the original question. I'm supposed to find the current I6 using Thevenin's theorem. So I did the first step of removing the Load resistor, short circuiting the voltage sources and calculating the equivalent resistance.
That makes it a lot clearer what you are doing now. I assume R6 was the load resistor and the R values are as you show in your own diagram.
In which case you need to add R1 and R2 in parallel, together with R3, R4 and R5 also in parallel.
On your original diagram you added R1 and R2 in series, for example.
1
#5
(Original post by Stonebridge)
That makes it a lot clearer what you are doing now. I assume R6 was the load resistor and the R values are as you show in your own diagram.
In which case you need to add R1 and R2 in parallel, together with R3, R4 and R5 also in parallel.
On your original diagram you added R1 and R2 in series, for example.
thank you so much!! Now after finding the resistance I am stuck at the mesh equations to find the current. I assume since there are 3 independent loops that means 3 unknown currents? However not sure how to write a mesh equation with 2 voltage sources in the same loop 0
3 months ago
#6
(Original post by sarah630)
thank you so much!! Now after finding the resistance I am stuck at the mesh equations to find the current. I assume since there are 3 independent loops that means 3 unknown currents? However not sure how to write a mesh equation with 2 voltage sources in the same loop If I understand your question correctly, the voltages (emfs) in a loop are added 'in series' but taking into account which way they are pointing.
So if you have, say, a clockwise current flowing round the loop, an emf with + pointing clockwise is positive and with + pointing anticlockwise is negative. Then use the single total emf added that way in your equation.
Last edited by Stonebridge; 3 months ago
0
#7
(Original post by Stonebridge)
If I understand your question correctly, the voltages (emfs) in a loop are added 'in series' but taking into account which way they are pointing.
So if you have, say, a clockwise current flowing round the loop, an emf with + pointing clockwise is positive and with + pointing anticlockwise is negative. Then use the single total emf added that way in your equation.
OH I see! Thank you!!!
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