- #1
Kirchhoff's Laws and Circuit Equation Help Request
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Homework Help Overview
The discussion revolves around applying Kirchhoff's laws to analyze a circuit, specifically focusing on calculating potential differences and understanding current relationships in loops. The subject area includes circuit analysis and electrical principles.
Discussion Character
- Exploratory, Conceptual clarification, Mathematical reasoning
Approaches and Questions Raised
- Participants discuss the relationship between currents in the circuit, questioning whether i3 + i4 equals i5. There are attempts to clarify the use of mesh analysis and Kirchhoff's voltage law, along with considerations of current continuity in loops.
Discussion Status
Some participants have offered hints and insights regarding the application of Kirchhoff's laws and mesh analysis. There is an exploration of different interpretations of the circuit setup, with no explicit consensus reached on the calculations or relationships yet.
Contextual Notes
There is mention of a short circuit affecting the potential difference calculations, and some participants note the need for additional equations to fully analyze the circuit. The discussion reflects a mix of assumptions and clarifications regarding current flow and voltage sources.
- #2
tiny-tim
Science Advisor
Homework Helper
- 25,837
- 258
hi sozener1! 
hint: the eg top-right-hand corner is also a node, and has one current going in and one current going out
sozener1 said:
hint: the eg top-right-hand corner is also a node, and has one current going in and one current going out
sooo … ? 
- #3
gneill
Mentor
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Note: Thread title changed to make it more descriptive of the thread content.
- #4
mr_pavlo
- 13
- 2
Hi,
actually you need only one more equation, since i1=i2, i3=i4 and i6 and i5 can be omited because they make no potential difference since they flow through short circuit.
So the last equation is 0=i3 x R + i3 x R - i7 x R
actually you need only one more equation, since i1=i2, i3=i4 and i6 and i5 can be omited because they make no potential difference since they flow through short circuit.
So the last equation is 0=i3 x R + i3 x R - i7 x R
- #5
Rellek
- 107
- 13
Hey there! It looks like this problem is just a use of mesh analysis without explicitly stating it.
So, if you look at the loop of wire that has the voltage source connected to it in series, you know that the current in that loop of wire must be constant. This is a fundamental principle of current.
What can you get from this? Well, it looks like i1 = i2 = i6
Not only this, but on the strand of wire on the right, this same principle can be applied.
If you use Kirchoff's voltage law around the first loop of wire on the left, you can see that:
(Going in defined direction of current) = V+i1R+i7R = 0, also, I think they made a mistake or misused the notation, because the shorter side of a voltage source is supposed to be the negative end.
From there, notice that i7 would have to be the net current between i1 and i3, and use the voltage rule around your second strand of wire in order to form another equation. After that, it is purely substitution, and assuming those R values are all equal, you'll have a nice result.
So, if you look at the loop of wire that has the voltage source connected to it in series, you know that the current in that loop of wire must be constant. This is a fundamental principle of current.
What can you get from this? Well, it looks like i1 = i2 = i6
Not only this, but on the strand of wire on the right, this same principle can be applied.
If you use Kirchoff's voltage law around the first loop of wire on the left, you can see that:
(Going in defined direction of current) = V+i1R+i7R = 0, also, I think they made a mistake or misused the notation, because the shorter side of a voltage source is supposed to be the negative end.
From there, notice that i7 would have to be the net current between i1 and i3, and use the voltage rule around your second strand of wire in order to form another equation. After that, it is purely substitution, and assuming those R values are all equal, you'll have a nice result.
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