Questions tagged [kirchhoffs-laws]

Kirchhoff's circuit laws deal with the conservation of charge and energy in a circuit.

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45 views

Finding the output of a node with two diodes (kind of full-wave rectifier)

Maybe this question sound stupid, but I really suck at electronics. I have this circuit here: simulate this circuit – Schematic created using CircuitLab and i want to find the values of ...
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Performing small signal ac analysis with non-linear components

I have written a circuit simulator that uses Kirchoff's voltage and current laws to solve linear circuits containing capacitors, resistors, inductors and op-amps (where the op-amps are assumed to be ...
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How can I find the voltage across R4?

I am trying to find the voltage across R4 in the following circuit: It confuses me that there are 2 voltage sources. I am not sure how to approach it, so I tried this: First, I use Kirchoff's ...
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Kirchhoff Voltage Law in a two port network

In a tutorial about h parameters of a two port network, I find the below snippet in the image unable to grasp. According to KVL, the total voltage in a loop is the algebraic sum of the individual ...
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Ideal Battery in Circuit

Does Kirchoff's voltage law hold when we connect a single battery to a circuit that has no other components. If it does hold, kindly let me know how. If it doesn't, how do we reconcile with that?
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Resistor Coefficient Voltage Matrix Doesn't have a Solution

Follow the link to the circuit that I need to solve for all the resistor voltage drops. I have to make 5 linearly independent equations in order to solve for all 5 unknown voltages. Using the loops ...
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Resources on Noise Circuits

Back when I was taking an RFIC design course, I was pretty disappointed by the noise part of the class, specifically calculating the output-referred noise voltage, noise figure of an amplifier, etc. ...
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3 Loop Circuit-Kirchhoff's Voltage Law(KVL)

I am struggling to solve the circuit given in the attachment. I have found the current values in the circuit and I am not sure about it(I do not have the answer sheet). I would like to ask whether it ...
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51 views

Should I perform Delta to Y before analysing the following circuit?

I am working on the following circuit: I am asked to find the node voltages at N1, N2 and N3. This problem seems pretty straight forward to me but the challenge I'm facing is due to resistor R4. ...
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How to solve for node voltages using mesh analysis?

I am given the following circuit to analyze: The problem asks me to solve for the unknown currents and then find the node voltages at N1 and N2. Here are the mesh equations I came up with: $$Mesh1$$ $...
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Output Voltage Formula verification of Operational Amplifier circuit

I'm trying to built an op-amp circuit for a PT100 temperature sensor. I've found the following circuit diagram online (from a polish website): And I'm trying to find the formula for the output ...
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63 views

How to write inductor ODE equation properly?

I've drawn a following scheme, and now want to write ODE system for describing inner processes, in order to explore it: simulate this circuit – Schematic created using CircuitLab I wrote the ...
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Finding current through a diode

I am asked to find the current through the second diode, as shown in the image below. I have gone through my procedure to find this current, and can not figure out why my answer is wrong. What I did ...
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Y-Δ transform with generators. Equivalence of three-terminal devices

So my book asks me to find \$i_a, i_b, i_c\$ (as functions of \$v_1, v_2, v_3\$) as well as \$G_a, G_b, G_c\$ such that the circuit on the right picture (shown below) is equivalent to the circuit on ...
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KVL On A Circuit With 2 Voltage Sources

I want to apply Kirchhoff's Voltage Law on the circuit showed below. When I apply it, I form this equation : $$-20 + Vx - 3Vx - 6i = 0$$ However, my book forms this equation: $$ Vx + 3Vx + 6i - 20 ...
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How can this circuit be solved with the node method?

I tried to solve this using the node method and it yields 0 on Mathematica, which I believe isn't correct. I'm trying to solve I1 first. simulate this circuit – Schematic created using ...
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1answer
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simple circuit analysis kcl kvl

can i know what, why and how this Rth is parallel / how its calculated? answer by jonk: thevenin analysis i mean my solution would be: I1 = I2+ I . I1 = (9-V2)/10k I2 = V2/20k I = V2-...
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Function generator output

A function generator is hooked up to two resistors in series. The voltage across the function generator changes over time, shown by the different graphs The questions asks to find the output voltage ...
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Clamper circuit, how to apply kirchhoff when the diode is turned around?

in this clamper circuit it's easy for me to determine the output waveform: This is how I do it: In the positive half cycle, the diode is forward biased with a drop of 0.7 V, so the positive half ...
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Solving a circuit with Nodal Analysis [closed]

I've been trying to start solving the circuit for a long time now, but I've no idea where to begin, what node should be grounded. Someone please solve this circuit ina detailed manner
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1answer
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Direction of current flow in resistor networks

We have a simple resistor network \$g\$ with \$5\$ nodes and \$6\$ edges (resistors) as given below: We assume all resistors have the same resistance (say \$1\$ Ohm, so homogeneously distributed ...
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Weird Kirchhoffs laws circuit

See image - I dont have any idea on how to start calculating this circuit using Kirchhoffs laws. There isnt any kind of this circuit anywhere on the web as far as I can see. I would be very thankful ...
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Basic electrical circuit loops

Hi I have a basic electrical circuit and I am trying to make loops. Those things on IMG-2. I just don't understand how are they made. Why are the "one square loops" only in upper squares and not ...
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KVL in the capacitor during transient analysis

I can see that this topic has been discussed many times in this site. But I still can't figure out why I am still not getting my correct equation applying the KVL. Consider a circuit as shown: ...
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Do photodiodes break KVL?

I know what you are thinking, but hear me out. Let's do KVL in this loop: simulate this circuit – Schematic created using CircuitLab We get: $$ -V_{PD}+I(R_s+R_L)-V_1 = 0 $$ Now we solve for ...
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Doing KVL on PNP BJT

I'm trying to find the voltage at the emitter and i use the property they give me of the absolute value VBE where in the book its equal to the small AC signal plus the DC VBE ( in this case that small ...
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How do I solve the current of this circuit with a diode?

I am trying to calculate the current of the circuit but I am unable to find the correct answer. I was able to solve the same circuit without the diode witch gave me 2mA. I am unsure of what to do with ...
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Find the current at the resistor

I've tried to divide current at 8A and then make a Kirchhoff voltage law between the resistor and dependent current source but I still can't solve it.
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Can I apply Kirchoff's law in the open contour in the picture

So is it right if I apply Kirchoff's law : Vcc=I1R1+I2R2+I3Re if I1 is the current that flows in R1 resistor, I2 in R2 and I3 in Re
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If the order of any component is altered in a series circuit, will the total voltage be affected?

I recently posed this question to someone. I always thought that the answer was simply no because of Kirchhoff's voltage law... However, their response was... "no, the voltage is not altered due to ...
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Matlab: Solving homogenous set of linear equations based on Kirchhoff's circuit laws

I have got the following equivalent circuit of a common source amplifier from which I want to determine the expression for the voltage gain A = VD/VG. Because I have pretty much more difficult ...
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62 views

Potential difference between these points

I do not know how to approach this problem or which theory to apply. Could you please help me to find out the potential difference between the points A and B in the circuit given below.
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As we go around the circuit, the total voltage drop must equal zero

I am studying an advanced mathematics textbook. One of the examples is within the context of an electrical circuit (a series circuit, I think). The example makes the following claim: As we go ...
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How is voltage divided between two reverse-biased ideal diodes?

Suppose we have two identical ideal diodes (without any resistance or voltage drop). We connect these two diodes in series, in the same direction, and reverse-bias them with voltage V. Now we have two ...
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Transistor circuit driving me insane

Consider the following circuit: Now I'm asking to impose the base current as zero and $$R_C=452.35 \Omega $$ Now I have a lot of issues with this circuit because I can't find a systematic way to ...
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2answers
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Can't understand a given answer about a 1st Kirchhoff's law question

I am currently studying the textbook "Lectures about the fundamentals of Electrical Engineering" by Adalbert Prechtl and after finishing the theory about Kirchhoff's law, I tried to solve some basic ...
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How do we get the negative voltage input value of this Op-Amp?

This is an exercise we did in class about the linear limitations of an Op-Amp, I get how we get the conductance and the Current value. But I don't understand in this KVL how did we get the value of $$...
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Does this experiment show that Kirchhoff's Law hold when there's a changing magnetic field involved in a circuit?

In this video, the electrical engineer and youtuber Mehdi Sadaghdar (ElectroBOOM) disagrees with another video from professor Walter Lewin. Basically, professor Lewin shows in an experiment that if ...
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What is the best approach to calculate the transfer function of this RC circuit?

I want to calculate the transfer function of the circuit below. I tried to calculate the equivalent impedance of each block and work my way with voltage dividers until I get to V3, but this method is ...
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Kirchoff law exercise

I need to determine the current across the 4 ohm resistor (name it I1). What I calculated, thought out so far : Current of 2 ohm resistor : I=5V/2ohm=2,5A. I Think this current is flow towards the A ...
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How can I solve for impedances if given RMS currents?

Given a very simple circuit such as this. If I where given the RMS values for the three currents, how could I go about solving R and Xl? (the resistor and inductor in paralell) I know I can not ...
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Calculate the Norton Resistance and Current and the Thevenin Voltage of the following circuit

U=10 V, R=10 ohm I calculated the resistance as such: 1/Rt = 1/R + 1/R <=> Rt = R/2 = 5 ohm To calculate the voltage I did KVL as such: U - 2Ur = 0 <=> Ur = 5V, where Ur is the voltage in the ...
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Calculating the Thevenin Voltage of this circuit

What I did was apply kirchoff's voltage law to the closed network with the 2 resistors and the voltage source to calculate the voltage of the resistors. I got U - 2*Uresistor =0 <=> Uresistor =5V ...
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Transistors, explanation of current gain

At this first picture i have a NPN transistor with Beta=75, 2N222A transistor, both Inputs are 5V. it was very simple to calculate the current that will flow through the LED. as it is simply I1 * Beta ...
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If we have four grounded nodes in a circuit, can we connect two of them together and forget that those two were grounds?

Refer to the image attached. I personally think the answer is no because it is not necessary for the currents through both the grounded capacitors to be the same in the upper circuit, but that is not ...
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i don't understand the KVL solution to this question?

this is part of the solution of a previous exam and there are some things i don't understand about it 1- why did he assume the value of current at the 12 Ohm resistor to be 0.5A without any ...
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Find potential difference between nodes A and B in circuit below

By KVL and KCL Ix = 4A and Iy=Iz=6A The potential difference between A and B = Va - Vb = 6 +8Ix =38V I don't understand how we calculated the potential difference using KVL and KCL
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LED's brightness difference in these 2 circuits

I have past exam's problem as follows. Suppose there are circuit A (left image) and B (right image). The question is why LED in circuit A is brighter than in B. The solution states that the Low-level ...
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Is this equation wrong?

I have a trouble in understanding one of the current equation in the following example: https://www.circuitlab.com/textbook/dependent-source-feedback/ To me i3 = (Va - Vb)/R2 which yields: Va - Vb ...
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135 views

Analyzing a constant current source

I'm looking at some old chemistry education literature where a constant current source was proposed (J. Chem. Ed. 1969, 46(9) p613, link). I am trying to better understand the circuit and could use ...