Questions tagged [kirchhoffs-laws]
Kirchhoff's circuit laws are important for circuit analysis. There are two laws: Kirchhoff's Current Law (KCL) and Kirchhoff's Voltage Law (KVL). KCL states that the sum of currents flowing into a node is zero, and KVL states that the directed sum of voltages around a closed loop is zero. Consider also using the "circuit-analysis" with this tag.
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Circuit theory basic problem
What approach do I have to take to find Vs. I don't really want an answer to this question but I want to know how to solve these circuits.
I'll first tell the approach I tried. I took KVL for all the ...
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Determining Thévenin voltage using nodal analysis
Here I want to determine \$V_{th}\$ without using mesh analysis and just by using nodal analysis. Now, \$V_{th}\$ is the same as the voltage across the \$6\ \Omega\$ resistor since no current passes ...
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Voltage distribution with two batteries [closed]
I have a question regarding a simple circuit of two batteries (9V) in series with a single resistor connected to the outer contacts to prevent a short.
When I'm simulating this circuit, a current also ...
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Find Thevenin's voltage
How could I find Thevenin's voltage in this circuit?
I can't use KVL since i don't know the voltage rise of the current source after removing the load.
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Two-port network
I have been trying to solve a problem on two-port network but I am getting two different answers:
APPROACH 1:
In the problem the Y-Parameter is given so I converted Y parameters to H parameters and ...
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Can an RCL circuit be asymptotically unstable? If so, what does that mean physically?
I'm analyzing the asymptotic stability of the system of ODEs that comes from an RCL circuit in series. Below is my circuit, with battery voltage \$u(t)\$, resistor with constant \$R>0\$, capacitor ...
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Voltage generation using 4 LEDs in series. Why does the voltage drop if I add a 5th LED in series?
I am making a device that doesn't use any batteries or outlet power.
I need it to momentarily (<1 s) produce 5V DC or more after a bright light is applied to a hole with a 10 mm diameter. Due to ...
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Calculations of mesh and nodal analysis of my dc circuit doesnt satisfy any of the KVL or KCL conditions
So I'm working on a course project under my professor and I seem to have encountered a huge problem.
I built my own circuit and solved it using mesh and nodal analysis in MATLAB, got some values but ...
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Amplifier circuit: Voltage divider x KCL
I was checking the solution to one question when I found out I couldn't use voltage divider rule to easy the formulas, the amplofier circuit (infinite gain):
My first attempt:
$$ V_{x}=\frac{R_4}{R_1+...
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How do you use nodal analysis to this circuit?
By using mesh analysis I have 4 equations:
6ia - 2ib = 24
-2ia + 12ib -20ic - 2id = 0
-8ib + 12ic = 0
-2ib + 12ic + 3id = 0
Got ic = 8/3 A, so Vo = 4(8/3) = 32/3 V ; correct me if I'm wrong
But I don'...
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Simplifying a Circuit for Nodal Analysis [closed]
I am trying to simplify/classify the following circuit:
My textbook says it is a four-node circuit but I am coming up with 3 nodes. Doesn't the "Ref." dot and the rightmost dot combine into ...
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Circuit reduction: Voltage across terminals [closed]
I'm new to electrical engineering and there is debate in my class about a problem. We are asked to find the voltage across A and B after reducing the circuit. Circuit is symmetrical.
Information given:...
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How to determine the directions of voltages across resistors in circuit diagrams?
In the following diagram, the directions of both currents and voltages for voltage sources are shown. My task is to write KCL and KVL for all 3 loops, and my question concerns KVL.
I believe I am ...
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Does current prefer to take a series path over a parallel path?
simulate this circuit – Schematic created using CircuitLab
Based on the simulation I have done, current here prefers to take the C1 - R2 path first and once C1 is saturated and cuts off it then ...
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Is there a sequence of thought I can do to solve complex circuits using only KVL and KCL?
This question took me a good 20-30mins of solving, and this just feels like a long time especially when I take my midterm exam it will only be 2 circuits in 1 hour only, so I need to make sure I find ...
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How does the current direction affect KVL?
I'm a bit confused about using KVL on circuits. For example, suppose I have this circuit, and we are given the direction of inductors current and capacitors current, and we have to find VA. Using the ...
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Current constant circuit
Did this circuit ok since no resistor on circuit? the voltage for each led is 3V for each led. Did i need to add resistor since 3Vx7=21V. The diode is led driver for 15mA. Btw, I'm designed for ...
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KCL confusion about currents direction
Sometimes when I use KCL for nodes in a circuit I cannot correctly determine the direction of the currents. My book also says that according to KCL the algebraic sum of currents entering a node is ...
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KVL/KCL and Thevenin Concept [closed]
I have solved the following question but little bit confused that this solution is correct or not as attached in figure.
How can I solve this question by KCL/KVL also if by using Thevinin theorem its ...
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Applying KVL to a grounded MOSFET circuit
I'm rather confused as to how to how this circuit doesn't violate KVL:
The two node voltages on the right side of the loop add to -4.16V, which means the voltages on the left should add to 4.16V, ...
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Derive a State-Space Model for an Electric Circuit with three Energy Storage Components
I want to model the shown circuit diagram with a state-space model. However, I cant solve it since I obtain four unknown variables while only three of the derived equations are linear independent. ...
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Why is my expression for current I(2) wrong?
simulate this circuit – Schematic created using CircuitLab
Hi!
My question is if I(2) is a current that runs from Node 1 to Node 2 then the expression of I(2) as a function of I(A), I(B), R1, R2 ...
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What is I1, I2, I3 and I4?
simulate this circuit – Schematic created using CircuitLab
I have really gotten stuck on this question where I need to calculate I1, I2, I3 and I4. The numbers for the circuit is: V(a)=2 V, V(b)=...
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How many measurements are needed to determine a black box with four terminals?
I am having a black box with four terminals and just resistors inside. I can model it like this:
simulate this circuit – Schematic created using CircuitLab
If I have four different currents and ...
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Transient Charge Density in Conductor
Veritasium's (Derek Muller's) video How Electricity Actually Works makes the claim at
4:44 that:
The truth is, if you average over a few atoms, you find the charge density everywhere inside a ...
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Why does the E-Field not change given two parallel capacitors?
I just cannot imagine, why connecting two voltage sources in parallel does not change the E-Field (strenghting it) and thus does not lead to higher voltage.
In this case charged plate capacitors are ...
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KCL in a particular node (problem)
Above is an AC circuit in which terminals A and B are used to connect to a load. I am asked to find the equations for currents coming into and out of nodes 1 and 2 (using KCL).
I had no trouble ...
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Why is clockwise KVL done like this?
My task is to find voltage across the resistor of this circuit where all the 4 components are connected in series with each other.
The given information are : V1 (t) = 100 * sin(100 * t) V, R = 100 ...
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Mesh loop analysis 2 loops, 2 voltage sources of different polarity
I'm having problems trying to work the following problem. The polarity is reversed on the right hand loop so I guess it becomes a -7v however does the current now go clockwise in loop one and anti in ...
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Inconsistent results on digital inputs (circuit review)
I am attempting to make a prototype automated testing jig for a ESP32S3 board with a Raspberry PI 3B+.
I am getting inconsistent results when reading the digital outputs state of the ESP32S3 on the ...
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Finding the voltage across the resistor and the phase angle for Vs [closed]
I used KVL to find the voltage across the resistor but how could I solve this if the phasor angle Vs is unknown? So far I only got the solution up until the equation for KVL which is
$$ V_s - V_l - ...
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(KVL) Different direction results different answers
Why does clockwise direction is giving one answer and anticlockwise giving different when applying KVL?
Fig E2.49 io (clockwise) = 13.33 mA and io (anticlockwise) = 0.02 A
Please help me point out ...
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I'm getting 11.547 kVA, but the answer is supposed to be 10 kVA. What am I doing wrong?
A 3-phase transformer bank consists of three identical 2300/230 V, 15 kVA single-phase transformers connected in delta/delta. The bank supplies a 20 kVA, unity p.f. 3-phase load. If one of the single-...
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How to apply KVL with current source?
In order to write an ODE for the inductor current I have to write a KVL equation that includes the current source. How do I do that?
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How to calculate unknown resistance from known current in the vector-matrix form of Ohm's law
I was trying to answer this question (pic 1) using the following method (pic 2):
Step 1. Apply junction law to find the current vector.
Step 2. Apply loop law to find the voltage vector and resistance ...
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How to apply KVL to MOSFET circuits?
I'm a little bit confused about applying KVL to circuits containing MOSFETs. I hope someone can provide some clarity. I'll be using the figure below to ask my questions.
First Question
If we want M1 ...
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How to apply Nodal Analysis on this circuit?
The two voltage sources are forming a supernode right?
should i take the resistance 6 ohms into consideration? How the solution will be?
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Trouble solving a specific KVL KCL question
Now I know this is newbie-ish kinda question but I was going over the basics of KCL and KVL, and encountered this problem:
For 1., I determine the drop using Ohm's law, ie. 2V
for 2-4 things get ...
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Can anyone help me with this circuit analysis problem?
The problem I have is that my answer depends on the assumption of the direction of I1. If I assume the direction of I1 to be like in the picture, I got I1 = 0.00005A and I2 = 0.00205A. The equations I ...
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KVL contradiction in LC circuit
Let's write down KVL in direction of current flow for an LC circuit.
We have 2 cases:
a) \$-\frac{q}{c} + L\frac{dI}{dt} = 0\$, which is wrong.
b) \$\frac{q}{c} + L\frac{dI}{dt} = 0\$, which is the ...
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Voltages around a loop
I am taking the voltages sum around a loop and I reached the following equation. Do you see any problem with it?
vC is the voltage of the capacitor.
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Am I applying KVL correctly to this very simple circuit?
We have this circuit:
I make the following assumptions about the current:
Such that $$I_1+I_2+I_3=0$$ at the blue junction. I then draw two loops, l_1 and l_2:
which yields the equations
$$-12 -...
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How to calculate current in a complex circuit? [closed]
Regarding a) How do I calculate the current for I1?
Regarding b) How do I calculate IA?
I have calculated I3 and I4 by using I = V/R and got the following:
I3 = 5 V/10000 Ω and
I4 = 5 V/100000 Ω
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Node method circuit analysis
There is my ungraded homework. I have watched many node method videos but they didn't help me in this question.
I'm struggling the determine where ground should be and choosing points A and B for ...
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Frequency response of coupled LC oscillators
We can use coupled LC circuit to understand the normal modes of coupled oscillators of a lattice.
We are using this to get the dispersion relation of the angular frequency for the oscillation.
...
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Analysing the behaviour of inductor in the circuit
Suppose we have an L circuit with DC power supply of emf \$\mathscr{E}\$
simulate this circuit – Schematic created using CircuitLab
By KVL,
\$\mathscr{E}=L\frac{dI}{dt}\$.
This suggests that \$\...
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Current and voltage relationship for superconductors
Before superconductors enter our everyday life, we must figure out a way to relate their voltage to current. For example, how would a circuit of two superconducting lamps in series behave? What if ...
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Is it possible to have a resistor network whose total value is unsolvable?
Home hobbyist here. I've been doing a lot of theoretical resistor, voltage divider, Ohm's law, and Kirchhoff law type problems just for practice, and ran across this older video on YouTube, which ...
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What is the overhead for calculating the number of LEDs for a given power supply?
simulate this circuit – Schematic created using CircuitLab
I have a series circuit with LED1 (2.0 Vf), LED2 (2.0 Vf), a 50 Ω resistor (1 V) and a power supply of 5 V. How much of an overhead ...
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How do I solve for the total resistance of this circuit with two loops sharing a resistor? [closed]
The values are in ohms. The loop in question is as follows:
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