Kirchoff's Rules Homework: Solving 3 Unknowns in a Circuit

  • Thread starter fsm
  • Start date
  • Tags
    Rules
In summary, the conversation discusses a circuit and the equations being used to solve it. The individual is having trouble finding the third unknown in each equation and is seeking help with using Excel to solve the simultaneous equations. It is also mentioned that there may be a typo in the first equation involving 800I3. Additionally, it is suggested to sum the voltages around different loops in the problem.
  • #1
fsm
88
0

Homework Statement


This is the circuit I'm working on:
cir.gif


Homework Equations


My equations are:
4.64v=-200I1-800I3
4.64v=750I3+800I2
4.64v=-200I1-750I3

The Attempt at a Solution


I should have a third unknown in each equation. I not seeing where I'm going wrong. I'm supposed to put this in a 3X3 matrix and have Excel solve for the simultaneous equations. Any help?
 
Physics news on Phys.org
  • #2
There are three different loops that you can sum the voltages around in the problem. The one involving R2 and R3 does not include the battery. So the sum around that loop should be zero. Your first equation also has an 800I3. Typo?
 
  • #3


I can offer some guidance on how to approach this problem. First, it's important to review Kirchoff's Rules and make sure you understand how to apply them in this circuit. Next, you can start by labeling the nodes and branches in the circuit and writing out the equations for each node and branch using Kirchoff's Rules. Make sure to include all the unknown variables in each equation.

Once you have your equations, you can set up a 3x3 matrix and use Excel or any other software to solve for the unknown variables. If you are having trouble setting up the matrix, try breaking down the equations into simpler forms and then rearranging them to fit into the matrix.

It's also important to check your calculations and make sure they are correct. If you are still having trouble, you can reach out to your classmates or instructor for help, or consult with a tutor or online resources for additional support. Remember, problem-solving in science requires patience, persistence, and attention to detail. Good luck!
 

FAQ: Kirchoff's Rules Homework: Solving 3 Unknowns in a Circuit

What are Kirchoff's Rules and how are they used to solve circuits with 3 unknowns?

Kirchoff's Rules are two fundamental laws in circuit analysis that are used to solve for unknown currents and voltages in a circuit. The first rule, Kirchoff's Current Law, states that the sum of currents entering a node must equal the sum of currents leaving the node. The second rule, Kirchoff's Voltage Law, states that the sum of voltages around a closed loop must equal zero. These rules are used to create a system of equations that can be solved to find the unknown values in a circuit with 3 unknowns.

What are the steps for solving a circuit with 3 unknowns using Kirchoff's Rules?

The steps for solving a circuit with 3 unknowns using Kirchoff's Rules are as follows:
1. Identify all the nodes and branches in the circuit.
2. Assign currents to each branch in the direction of your choice.
3. Apply Kirchoff's Current Law to each node, setting the sum of currents entering the node equal to the sum of currents leaving the node.
4. Apply Kirchoff's Voltage Law to each closed loop in the circuit, setting the sum of voltages equal to zero.
5. Solve the resulting system of equations for the unknown values.
6. Check your solution by ensuring that Kirchoff's Rules are satisfied for all nodes and loops in the circuit.

Can Kirchoff's Rules be used to solve circuits with more than 3 unknowns?

Yes, Kirchoff's Rules can be applied to circuits with any number of unknowns. However, as the number of unknowns increases, the system of equations becomes more complex and may require advanced techniques such as matrix methods to solve.

How do I know if my solution to a circuit with 3 unknowns is correct?

A solution to a circuit with 3 unknowns is considered correct if it satisfies both Kirchoff's Current Law and Kirchoff's Voltage Law for all nodes and loops in the circuit. Additionally, the solution should have realistic values for currents and voltages, and should not violate any known physical laws.

Can Kirchoff's Rules be applied to circuits with non-linear elements?

Kirchoff's Rules can be applied to circuits with non-linear elements, but the resulting equations may not be solvable by traditional methods. In these cases, other techniques such as numerical methods or circuit simulation software may be necessary to find a solution.

Similar threads

Replies
6
Views
2K
Replies
7
Views
2K
Replies
3
Views
2K
Replies
20
Views
3K
Replies
9
Views
1K

Back
Top