How to analyze a circuit with one node using the node method

In summary, the conversation discusses using the inspection method to solve a circuit problem involving a single node. The necessary equations and matrices are provided, with a reminder to use the conductance matrix instead of the resistance matrix. The final solution involves taking the inverse of the conductance matrix and multiplying it by the current matrix.
  • #1
Boltzman Oscillation
233
26

Homework Statement


I have the circuit given below with a single node where R3 and ground meet. How can I solve this problem using the inspection method? Is it possible? I can easily solve using another method but I would rather try using the inspection method.

Homework Equations



Ax = M
A is the resistance matrix obtained via inspections
x is the voltage matrix
M is the current matrix

The Attempt at a Solution



Since there is only one node then my resistance matrix, obtained using inspection, will only have one row and one column. Thus in this case:

A = [ 17000]

The voltage matrix will only have my one at the node:

x = [V]

finally the current matrix will have the sum of all the current sources going into the node (subtract those going away):

M = [1mA + 1mA] = [2mA]

I can take the inverse of A and then multiply it by M to get:

x = A^-1 * M
or
V = 2mA/17000
which i believe is the wrong answer. Am I wrong? Can I even solve this using inspection since it is only one node? Thanks.
circuitNode.png
 

Attachments

  • circuitNode.png
    circuitNode.png
    2.6 KB · Views: 334
Physics news on Phys.org
  • #2
Since this is nodal analysis you'll want the conductance matrix, not the resistance matrix. Those current sources appear to be 1 Amp each, not one milliamp each.
 
  • Like
Likes scottdave
  • #3
gneill said:
Since this is nodal analysis you'll want the conductance matrix, not the resistance matrix. Those current sources appear to be 1 Amp each, not one milliamp each.
OMG I totally forgot about that! Thank you Thank you!
 

1. How do I identify the nodes in a circuit?

To identify the nodes in a circuit, you need to look for points where multiple components are connected together. These points will be labeled with a node number, such as N1, N2, etc. In some cases, there may also be a reference node, usually labeled as ground (GND).

2. What is the node method used for in circuit analysis?

The node method, also known as the node voltage method, is used to analyze circuits with multiple nodes. It involves writing equations based on Kirchhoff's current law (KCL) at each node and solving them simultaneously to determine the voltage at each node.

3. How do I apply Kirchhoff's current law in the node method?

Kirchhoff's current law states that the sum of currents entering a node must equal the sum of currents leaving the node. To apply this law in the node method, you need to write an equation for each node, setting the sum of incoming currents equal to the sum of outgoing currents.

4. Can I use the node method for circuits with multiple voltage sources?

Yes, the node method can be used for circuits with multiple voltage sources. However, you will need to consider the polarity of each voltage source when writing the equations for each node. The voltage source with the higher potential will have a positive sign in the equation, while the lower potential source will have a negative sign.

5. Is the node method the only way to analyze a circuit with one node?

No, there are other methods for analyzing circuits with one node, such as the mesh method and the superposition method. The node method is often preferred for its simplicity and efficiency, but the choice of method may depend on the specific circuit and personal preference.

Similar threads

  • Engineering and Comp Sci Homework Help
Replies
10
Views
2K
  • Engineering and Comp Sci Homework Help
Replies
6
Views
1K
  • Engineering and Comp Sci Homework Help
Replies
4
Views
1K
  • Engineering and Comp Sci Homework Help
Replies
5
Views
976
  • Electrical Engineering
Replies
3
Views
744
  • Engineering and Comp Sci Homework Help
Replies
7
Views
895
  • Engineering and Comp Sci Homework Help
Replies
12
Views
1K
  • Engineering and Comp Sci Homework Help
Replies
7
Views
2K
  • Engineering and Comp Sci Homework Help
Replies
7
Views
886
  • Engineering and Comp Sci Homework Help
Replies
1
Views
1K
Back
Top