Linear Algebra Question on Calculating Current

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SUMMARY

The discussion focuses on calculating the current in a circuit using linear algebra, specifically through the application of Kirchhoff's laws. The user identifies a circuit with 6 loops and seeks guidance on constructing a matrix to solve for the currents through each resistor. The solution involves creating a system of equations based on Kirchhoff's current law (KCL) and Kirchhoff's voltage law (KVL), resulting in |L| + |N| linear equations, where |L| represents the number of loops and |N| the number of nodes.

PREREQUISITES
  • Understanding of Kirchhoff's Current Law (KCL)
  • Familiarity with Kirchhoff's Voltage Law (KVL)
  • Knowledge of Ohm's Law (E = iR)
  • Basic skills in linear algebra and matrix operations
NEXT STEPS
  • Learn how to apply Kirchhoff's laws in circuit analysis
  • Study matrix methods for solving systems of linear equations
  • Explore advanced topics in linear algebra, such as eigenvalues and eigenvectors
  • Investigate circuit simulation tools like LTspice or Multisim for practical applications
USEFUL FOR

Electrical engineering students, circuit designers, and anyone involved in analyzing electrical circuits using linear algebra techniques.

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Hi everyone

I am trying to find the current of a circuit using linear algebra.
So far, I know that there are 6 loops, one on each side of the cube. However, I am not sure about how many equations I have to come up with to construct a matrix and thus solving the problem.

The questions is to find the currents that are going through EACH resistor, and the DIRECTION that they are going in. There should be a total of 12 arrows indicating the directions of the currents, 1 on each side.


ANY help/hint/suggestion is GREATLY appreciated.
 

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Are you referring to the application of Kirchoff's (and Ohm's) laws?

In this layout, you have equations for each node and each loop in the circuit.

Is that your layout?
 
Last edited:
I'll post the layout, together with the solution for a specific circuit,( I'll do
so if anyone is interested):

Given a circuit with x nodes and y loops, we use the fact that (Kirchoff )

i)At every node, the sum of incoming currents equals the sum of outgoing currents.

ii) Around every loop, the (algebraic) sums of the increases in voltage equals the
sum of voltage drops.

Then, we must have , for a given node N in the circuit:

c_N1 +..+c_Nj +...c_Nn =0

( I'm getting some cash back for that c_Nn plug, BTW.)

where ci is the value of the current, and it is positive if the current is
incoming, and it is negative otherwise.

For every loop L , we use Ohm's law (E=iR ) to calculate voltage drops:

iR_L1+..+iR_Lk+...+iR_Ln=0

From this, you get a system of |L| +|N| linear equations, from which you get the
currents.

Is this what you're looking for?
 

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