In electric circuits analysis, nodal analysis, node-voltage analysis, or the branch current method is a method of determining the voltage (potential difference) between "nodes" (points where elements or branches connect) in an electrical circuit in terms of the branch currents.
In analyzing a circuit using Kirchhoff's circuit laws, one can either do nodal analysis using Kirchhoff's current law (KCL) or mesh analysis using Kirchhoff's voltage law (KVL). Nodal analysis writes an equation at each electrical node, requiring that the branch currents incident at a node must sum to zero. The branch currents are written in terms of the circuit node voltages. As a consequence, each branch constitutive relation must give current as a function of voltage; an admittance representation. For instance, for a resistor, Ibranch = Vbranch * G, where G (=1/R) is the admittance (conductance) of the resistor.
Nodal analysis is possible when all the circuit elements' branch constitutive relations have an admittance representation. Nodal analysis produces a compact set of equations for the network, which can be solved by hand if small, or can be quickly solved using linear algebra by computer. Because of the compact system of equations, many circuit simulation programs (e.g., SPICE) use nodal analysis as a basis. When elements do not have admittance representations, a more general extension of nodal analysis, modified nodal analysis, can be used.
I spent the whole day trying to figure why transresistance amplifier modelled with z-parameters does not match with nodal analysis results but I sill can't figure out. I desperate need help on this...
I write down step by step what I did for a very simple transresistance amplifier here and hope...
Hello,
I came up with a circuit that has two independent voltage-controlled current sources. I want to calculate voltage gain: ##G_{U} = \frac{U_{2}}{U_{1}}##. Moreover, I want to practice the nodal method at the same time. Below I'm sending schematic with marked nodes V1, V2, V3 and V4.
I...
Hi there, I have managed to work out the kirchoff's law bit but for the other two bits I just cant get started as I can get my head around it, its due in on monday I dont know why I left it so late!
Hi first time using this forum, I have some homework that I am entirely stuck on, can anyone help me with this question? I understand the placement of nodes, and that I need to convert complex numbers, but apart from that I have no idea what direction that I'm supposed to take in this. I don't...
Here is the question
a. Plot nodes in the problem and indicate how many equations will be obtained.
answer: two unknown variables
b. Use node analysis. Derive the system of equations for the voltages in the circuit.
question: Did I calculate right V_a and V_b?
C. Calculate the...
Hello! Consider this circuit
Now I am susposed to solve this using nodal analysis. The first step is to "prepare the network" so that I can set up the conductance matrix.
Now I've tried it for a bit and was not really able to do it. So I went ahead and looked at the solutions and this is how...
Summary:: The image shows two circuits, in the first one, using Nodal Analysis we find that V1=4.8V, but in the second circuit V1=10 because using KCL - 10+V1=0. I understand what happened in the first circuit, but I don't understand what happened in the second one, they look the same to me...
*A is the node all the way to the left above the 30V but I didn’t end up using it because I don’t think you need it since the same as 30V, right? *
I know I messed up somewhere because shouldn’t V1-4 = 30? After finding my V1 I used that value to find the other Vs and it ended up being close to...
I have tried many times to solve this network, but can't understand how to get current in each resistors by superposition theorem. Please help me to solve and find currents in each 3 resistors with solution.
Note:- The figure is attached below.
Hi all,
Managed to get an answer out, but unfortunately, it doesn't correspond with the answer given ( –3.09 A)
Would appreciate if one could check out what I did wrongly here:
## V_{1}=2\times 5=10V ##
At node 2:
## \dfrac{V_{1}-V_{2}}{2}=12+\dfrac{V_{2}}{1}+\dfrac{V_{2}-V_{3}}{2}##
We can...
Was just practicing some problems on the Fundamentals of Electric Circuits, and came across this question.
I understand I will have to transform to the s domain circuit, which looks something like this:
Then doing nodal analysis, I will get the following for the first segement
(10/s-V1)/1 =...
Summary: Perform nodal analysis on a circuit to find voltages.
For a laboratory I am trying to find the nodal voltages for a circuit we built using hand calculations. I have the answer as we ran the simulation which shows all the nodal voltages, however my nodal analysis seems to be wrong as I...
I'm asked to solve for Vo for this equation. I've set the bottom node to be my reference node before applying nodal analysis. When included in the KCL equation for node at Vb, will the dependent voltage source 20iΔ be negative since the current through that element is leaving node C?
Say, the...
That is, for Supernode -1,3 (12V branch) , we do Nodal Analysis and we have (V2-V3)/2 , over the 2 ohm branch.
But this current is not included in the Equation 1 in the solution I have attached(Which is my only source to cross check answers/solution right now.)
Is the solution wrong?
Thanks...
My attempt:
At node 1 > 4 = 6 + I1
Node 2 > I1 + I2 = I 2
Node 3 > 6 = I 3 + I 4
I1 = (V1 - 4)/21
In node 1,
Using the equation for I1, V1 = -38V.
I2 = (V1 - 4 - 1)/2
So, I2 = -21.5APower supplied by the 1V battery is
P=VI
P=-21.5 x 1
P=-21.5W
I am not sure of my method, I just started...
Hello,
My name is Muhammad Imron aka imronuke. I am interested in nuclear reactor computation and currently developing open reactor simulator called ADPRES which you can find in the my github repository.
Regards,
Homework Statement
Hi I have this question as part of my assignment but cannot get my head around part b, I have worked out part a with an answer of -9.2+17.3i amps which from a previous thread I know is correct, but can't understand why the equations given in the previous thread are different...
Homework Statement
[/B]
Determine, Using the values given in TABLE A, the current I in the circuit of figure 2 by
(a) Mesh analysis
(b) Nodal analysis
Circuit diagram and given variable attached.
V1 = 120
V2 = j120
V3 = 14.142+j14.142
Z1= 2
Z2=-J5
Z3=4
Z4=-J5
Z5=J4Homework Equations
[/B]
KVL...
Homework Statement
Find i using Nodal Analysis.
Homework Equations
V = I * R
The Attempt at a Solution
solve (1) , (2) , and (3) to find V1 , V2 ,and V3
V1 = 50/3 = 16.67 V
V2 = 80/3 = 26.67 V
V3 = 40 V
40 - 80/3 = 5i
i = 2.667 A
However , the correct answer is 1.522 A .. I don't know...
Homework Statement
The problem states: Determine the voltage labeled v in the following circuit: https://ibb.co/hz0Q37
The variable is the voltage across the 2 ohm resistor. The ground I chose for this example is located in the center of the circuit.
Homework Equations
V=IR I guess.
The...
Homework Statement
Homework EquationsThe Attempt at a Solution
I have attempted and completed all questions. However, I am now trying part (b) with transforming the voltage source into a current source. I am unable to work out the current and I am unsure what to do next.
I have included my...
In node analysis, after labeling the nodes. I don't know how to choose currents direction to apply KCL. it seems too complicated.. and I end up every time getting different answers the the solution sheet. I've an exam tomorrow. would be much appreciated if you could help me better understand the...
Homework Statement
Homework Equations
using nodal analysis
The Attempt at a Solution
https://imgur.com/a/UNEDH
the excel sheet is the matrix i set up then used cramer's rule. I think i got the method down but i just can't find the error so hopefully i overlooked something.
The equation i...
Homework Statement
Here is a diagram of the circuit and my redrawing with currents drawn:
We are to find the power delivered by the dependent voltage source. I found a solution online, but I am not sure why they had the KCL line as:
$$ \frac{v_1 - 160} {10} + \frac{v_1} {100} + \frac{v_1...
Homework Statement
Homework Equations
##V = IR##
##\sum_{k = 0}^{n} I_k = 0##
The Attempt at a Solution
[/B]
I set the bottom node as the reference node and worked from there to find the three equations for the loop. When I try to eliminate ##I_4## by using ##I_4 = I_2 - I_3## I run into...
1. Homework Statement
The circuit is driven by a voltage source,
Vs(t)= 8.2 cos(1.8 t − 0.25 )V .
The circuit elements are given as follows.
G1= 5 S,G2= 7.6 S,G3=3.8 S
(Gi is the conductance of corresponding resistor Ri)
L1= 20 H,C1= 5×10−2 F
If we select Node 4 as the reference node...
Homework Statement
This particular question has been raised in past posts and I have studied those posts but unable to take anything from them. Basically the question comprises 2 parts. Part A requires us to find the current through "I" using mesh analysis. By studying some of the posts on...
Homework Statement
(a) Apply Nodal Analysis, writing down the equations which determine VA and VB, the voltages at nodes A and B [8]
(b) Find values for VA and VB. [4]
(c) By calculating the currents supplied by the 44 V and 2 V sources, or by any other means, calculate the total power...
Homework Statement
Determine the output voltage Vo(t) in terms of Vs
Homework EquationsThe Attempt at a Solution
If I were to use Nodal Analysis to solve this, would these be the proper nodal equations?\frac{V1}{-j1.6} + \frac{V1-Vs}{175} = 0
\frac{V_{I2}-Vo}{10k} + \frac{V_{I2}}{1k} = 0
Hey, I am having problems with this. I need help with these 2 circuits I am basically lost and not sure how to start. I need to find voltage, current and potency on each resistance
help would be much appreciated, thank you
http://imgur.com/trm1On0
http://imgur.com/a/KD3zr
Homework Statement
Find Va(t) using Nodal Analysis:
Homework Equations
Zc = 1/(jwC)
Zl = jw*L
The Attempt at a Solution
W = 250
Z36mH = j9 ohm
Z80mH = j20 ohm
Z0.25mF = -j16 ohm (is capacitor impedance always negative? It says so in my instructor's notes but I forgot why)
20cos(250t) ->...
Homework Statement
Attempted Solution:
For my two nodal equations, I got:
40j + 20 - 12Va*j + 2Vb *j +4Va - 4Vb = 0
and
2Vb - 2Va - 6Vb*j - 4Va*j-10-20j
Are these right? How do I solve this system of equations?
Homework Statement
[/B]
Find I by mesh and nodal analysis
Homework EquationsThe Attempt at a Solution
##V_{10}## is defined at the junction of ##Z_1##, ##Z_2## and ##Z_4##.
##V_{20}## is defined at the junction of ##Z_2##, ##Z_3## and ##Z_5##.
##0V## is defined at the junction of ##V_1##...
Homework Statement
Attached is a image of the circuit that I am attempting to analyze:Homework Equations
KCL
The Attempt at a Solution
So I know I should assign a place in the circuit where I should preform KCL after selecting a reference point.
I selected the reference point as the 2ohm...
Homework Statement
Homework EquationsThe Attempt at a Solution
If I take KCL at node V1 (I'm assuming current traveling from nodeV2 to node V1)
Current in = Current out
V2 - 2volts / 2 ohms = V1 / 8 ohms
so my question is, how does the battery (2 volts in this case) play a role in nodal...
Problem is in the picture below.
The problem is already solved, but I am confused as to why C(dv/dt) is positive and not negative, since the current is coming out of the capacitor and towards the point v(t), which is not away from v(t) like the solution shows. But if I solve the problem with...
I was doing the following problem:
And I was asked to find Iy.
I found Iy to be 2.64 using KCL. However, the right answer was negative 2.64.
Is it negative only because there is a dependant voltage source with "+ -" ? And why must it be negative? Does "-" in the final answer play a...
While performing nodal analysis problems, I am always unsure of which node gets subtracted from during KCL. For example, if I have (V1-V2)/2k, how do I know that it shouldn't be (V2-V1)/2k?
Homework Statement
Assignment: Find V_2 using Nodal Analysis
Homework Equations
KCL
U=R*I
The Attempt at a Solution
- Chosen reference node
- Assigned node voltages
- Applied KCL to each non-reference node
- Solve system of equation
- Checked equations for obvious errors
See circuit drawing...
Homework Statement
In attached image. Just curious as to how their nodal analysis is correct.
Homework Equations
[/B]
##I_{in} = I_{out}##
The Attempt at a Solution
Solution in image.
I am just not sure how they applied nodal analysis here to find that ##I_s = \frac{12}{12} +...
Homework Statement
Use nodal analysis to calculate Va, Vb, and the currents IE1 and IE2 without using source conversions
I have tried this many, many times, and I must be missing somethingHomework Equations
[/B]
The equations I came up with:
VA-10/ 1.1 + VA/1.2 +VA-VB/1.4 = 0
VB+2/1.5 +...
Homework Statement
The Attempt at a Solution
[/B]
At node B,
##i_s + 3 = i_2##
## 3 + 3 = i_2##
##i_2 = 6A##
##V_2 = i_2/R_2 = 3V##
But, it seems that the answer is wrong. Using superposition method, the voltage is 4V
Please tell me where I got wrong
Homework Statement
Find Voc
Homework EquationsThe Attempt at a Solution
This is what I have:
(VA-9)/5 +VA/5 + 1.8 = 0
VA=0
-1.8 + VB/(60+10) +(VB-9)/20
VB=35
What I'm confused about is why you combine the 60 ohm and 10 ohm resistors for the VB nodal equation, but not the 25 ohm and 10 ohm...
Homework Statement
*Posted in the Screenshot*
Homework Equations
*Posted in the uploaded attachment*
The Attempt at a Solution
*Posted in the uploaded attachment*Hi all.
Our lecturer gave us the question as part of an assignment but I'm not to sure if my approach and answer is correct. I...
I've been assigned the following problem for homework in my Electrical Engineering class:
*Note, the duplicate v2 is supposed to be v3.
But I keep getting
v1 = 4.10V
v2 = 4.81V
v3 = -1.19V
and
i0 = 52.9mA
Every simulator I've put this into says it's wrong, yet I've attempted solving it...