Questions tagged [passive-networks]

Use this tag for circuits that only contain passive components, such as resistors, capacitors, and inductors. This includes RC, RL, LC, and RLC circuits.

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222 views

RLC equivalent model and Impedance Smith Chart

I have done some impedance measurements on an unknown 1 port device. I have measured its impedance at different frequencies (from 10 MHz to 600 MHz) and I have seen it on the normalized (on 50 Ohm) ...
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62 views

Generate identical positve going and negative going pulses/spikes at the same time

I am interested in building a circuit to generate a sharp positive pulse and an identical negative pulse at the same time with a peak of about 10 to 200 V. So when I say sharp I would like a rise time ...
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285 views

Mosfet LC oscillator

I'm looking at the following circuit: simulate this circuit – Schematic created using CircuitLab It consists of an oscillation whose frequency depends on the tank circuit (C1, L1 and L2). When ...
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4answers
2k views

The Intuition for RLC circuits

I'm reading through Hayt's Engineering Circuit Analysis 9e and it does a fairly good job of giving the intuition for "where" the energy is going in a damped RLC circuit, but I'm hoping that someone ...
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2answers
96 views

Query on writing KVL equation for an RL circuit

Say I have the inductor in the following circuit with certain current already in the circuit flowing in the specified direction: simulate this circuit – Schematic created using CircuitLab If I ...
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2answers
125 views

What does a simple passive circuit to simulate an impedance mismatch look like?

I am trying to learn some of the basics of circuit design. One thing I am curious to make a filter/schematic of is what happens when a voltage source hits an impedance mismatch. eg. A high impedance ...
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28 views

Initial conditions in multi-state Tesla Coil circuit

Half a year ago I posted this quesion about a Tesla Coil resonant circuit which got an amazing answer that helped me understand the resonant frenquency of such circuit. Now I've returned to that ...
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37 views

Infinite hexagonal impedance network with loads at specific nodes

It's been a couple weeks already that I am trying to solve this network on the paper. It consists on a infinite/periodical hexagonal lattice but with some peculiarities. First of all, this is not the ...
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2answers
82 views

2nd order Low-Pass Output Impedance and Phase difference

I am trying to calculate the output filter impedance and the phase difference of the inverter that I am designing. However not sure how to construct a formula for both the output impedance and phase ...
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1answer
31 views

Solving a series RLC DC step response circuit

I got two different answers to this RLC problem when using a method shown in class. What am I doing wrong? Edit: I graphed each answer. I'm assuming the answer for Vc on the right is correct, as the ...
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100 views

RLC Circuit with Dependent Source

I am trying to solve the attached practice problem from Hayt's 8e of Engineering Circuit Analysis but I am struggling to find a solvable differential equation for the circuit. I am trying to use KVL ...
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156 views

Low pass LC filter goes “wrong” with capacitive load

I have been experimenting with this circuit: simulate this circuit – Schematic created using CircuitLab Vin has a lower frequency ripple of 2V and a high frequency (switching?) noise of 6.5V. ...
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3answers
116 views

Why is the impedance zero at cutoff frequencies in a series RLC resonance circuit?

I see that, in many derivations in the frequency analysis of series RLC circuits, \$X_L - X_c = R\$ or \$Xc - X_L = R\$ is considered at lower and higher cutoff frequencies. So does that mean that the ...
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1answer
70 views

Finding current in RLC circuit

I am given the following circuit: Thanks for any help.
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1answer
77 views

Ambiguity in the Definition of Resonance Frequency

we know that in a series LC circuit the resonance frequency is defined as that frequency in which the total impedance offered by the circuit is zero. We also know that in a parallel LC circuit the ...
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150 views

RFI filter modeling in LTspice w/ triac

I have a few questions about modeling an RFI filter in LTspice with a triac-based dimmer circuit. I'm referencing the circuit described in Figure 11 in Triac Principles and Circuits -- Part 2 (Nuts &...
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1answer
158 views

State variable equations for a RLC circuit

What are the state variable equations of this RLC circuit? How do I write the final matrix? I tried to write the equations for the capacitor and inductor: $$L\frac{di_3}{dt}=v_1-v_C \leftrightarrow \...
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2answers
108 views

What of value of R result in V=0

As shown the answer is 15 Ohm's . I don't get the trick of the question. can anyone explain to me how we can get the value of R Thank you all!
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88 views

LC CIRCUIT ISSUE

I am high school boy doing his homework on the circuit, I came across this question , I need to find maximum current that will flow in the circuit What I have tried :) It's a weird one because ...
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1answer
108 views

RLC initial conditions

I am working on the following series RLC circuit: Let the circuit have non-zero initial conditions \$I(0^+)= 6\text{A}\$ and a voltage across the capacitor of \$V(0^+)=-12\text{V}\$. What are \$\...
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3answers
1k views

Computing the voltage across a parallel LC component at resonance?

Problem For the circuit illustrated below, I am trying to compute the sinusoidal voltage across resistor \$R_{1}\$ when the parallel LC component is in resonance: I setup my problem with the ...
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1answer
363 views

How to find Vo in a circuit with two voltage sources

I do not know how to find Vo in this circuit. According to my notes about how to take node voltage, I get 0 = Va + 6.857 V + 0V Vo = Va But that doesn't sound right. And I get a different answer ...
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2answers
321 views

555 Timer - How to quickly discharge RC capacitor

I'm using a 555 timer to turn off an LED with delay. Here is the circuit. All I want to implement is, to get the input voltage changes in output with a constant delay. When I close the switch, the ...
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0answers
121 views

Struggling to get an amplified sine wave over a small inductor at low frequencies

I am building a power amplifier circuit to amplify a sine wave over an inductor from a function generator. However because the inductor is small and i'm running at a low frequency I am getting ...
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1answer
122 views

Measuring the quality factor RLC circuit

I am trying to get the Q factor for this circuit but I don't know how to simulate it properly. I did a frequency sweep from 1 Hz - 30 MHz. The oscillating frequency is 16 MHz. I can't get the ...
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1answer
63 views

Help me see if I understand this RLC circuit

The switch closes at t=0 I need to determine the current and the voltage of Capacitor at t=0.25s at t<0 the switch is open there is no current and no voltage at t=0 the switch closes the current ...
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1answer
102 views

Capacitors capacity in an RLC circuit that is in resonance [closed]

So if its in resonance that means XL=XC right? anyway thats how I started I∠=Irms∠=7.07/sqrt2 ∠30° A ω=10^3 Z1=R+jXL=1+1∠90°=sqrt2∠45° Z2=-jXC=1∠-90° Ztotal=(1/Z1+1/Z2)^-1=sqrt2∠-45° U∠=I∠*...
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1answer
167 views

How does the second order time constant affect circuit behavior?

I learned that the transfer function of a second order circuit can be expressed in the following standard way: $$ \frac{K}{\tau_s^2 s^2 + 2 \zeta \tau_s s + 1} $$ Where: \$K\$ is the gain \$\zeta\$ ...
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1answer
49 views

Are these valid transformations, Please guide

Please help check if the transformations in the pink are allowed, when solving a circuit. For the given circuit the goal is to find the current I1 which could be found using nodal without taking care ...
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1answer
197 views

Is my circuit solution correct?

simulate this circuit – Schematic created using CircuitLab I have to calculate the energy of the inductors magnetic field at t = 6 ms. I am given: E = 50 V, R1 = 10 Ω, R2 = 15 Ω, R3 = 20 Ω and ...
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2answers
69 views

I have to find all the voltages and current in the circuit

I am given Uab=100V XL=6Ω XC=3Ω R=4Ω This is how I started X=XL+XC=9Ω Ztotal=sqrt(R^2+X^2)=9.84Ω Zab=R+jXL=4+j6=7.21∠56.30 I=Uab/Zab=100/7.21=13.86A but obviously I made a mistake somewhere ...
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1k views

RLC circuit: how to find voltage/current derivatives and derive differential equation

Trying to resolve differential equations for RLC-networks, I'm always stumbling upon the voltage/current derivatives. Here I would like to give two examples from the same textbook and explain my ...
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1answer
133 views

Differential equation for a notch filter RLC circuit

I'm trying to write and solve a differential equation for this simple RLC notch filter and I'm not sure what I'm doing wrong. simulate this circuit – Schematic created using CircuitLab So ...
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1answer
491 views

Parallel RLC Circuit: how to write differential equation?

Please consider the following circuit: At t>0 this circuit will be transformed to source-free parallel RLC-circuit, where capacitor voltage is Vc(0+) = 0 V and inductor current is Il(0+) = 4. Now is ...
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4answers
366 views

What are AC and DC transients, rather do we even classify transients that way?

We are provided a syllabus in our university stating "Unit III - Transient responses of RL,RC,RLC circuits, DC and AC sinusoidal input". As far as I can see, "transients" are the response a circuit ...
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1answer
240 views

Find Io(t) of RLC circuit (from Electric Circuits, Nilsson )

My question is from the Electric Circuits, Nilsson 10th edition. My solution is For \$t < 0\$, we get \$i_o(0) = 2 \mathrm{A}\$ and \$v_o(0) = -400 \mathrm{V}\$. For \$t > 0\$, the circuit ...
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1answer
55 views

Should we include Source and Load Impedance while calculating two port parameters?

While calculating the \$Z\$, or \$Y\$ or \$h\$ parameters of a two port network, should we include the source impedance and load impedance or not? In other words, for finding \$Y_{11}\$, we short the ...
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2answers
83 views

Kirchoff's Law Problem

We were given a circuit with 7 resistors and 3 voltage sources For emf sources, \$E_1=120V\$, \$E_2=60V\$, and \$E_3=30V\$ while for resistors in ohms,\$R_1=10\$, \$R_2=5\$, \$R_3=20\$, \$R_4=8\$, \$...
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4answers
261 views

Quality factor in arbitrary RLC resonance circuits

I am looking for a way to calculate the quality factor in arbitrary RLC circuits not just standart series or parallel circuits. It would be great, if anybody could provide a formula and some further ...
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1answer
866 views

Calculating energy absorbed by an element

I need your help to understand the solution to the given question where energy absorbed needs to be calculated with the given graphs of the current and voltage through the element. Please help explain ...
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1answer
40 views

di/dt for R of general RLC, KCL dt algebra

Basic question. This is an exercise which requires all initial values for i and v0 (both 0), final values (yielding 2,4 A and 9,6 V) It also asks for di/dt and my question lies on the answer given (...
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3answers
139 views

Electrons inside an LC Circuit

I am having some trouble understanding the behaviour of electrons inside an RC circuit. Let me explain: One capacitor plate accumulates a lot of electrons, which pushes electrons away into the ...
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3answers
874 views

How do I remove this power supply noise?

Above is the circuit diagram of my power supply. It converts input 12V DC into 5V DC and then 3.3V DC with linear regulator. I have highlighted it in red color in the block diagram. So current ...
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71 views

How to find Rth for the Thevenin Equivalent Circuit?

So we were given this circuit to solve for I1, I2, I3, and lastly the Thevenin Equivalent Circuit. I was able to solve for I1, I2, I3. However I am having a hard time computing the RTH at ab. Here is ...
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50 views

How to do Transient analysis?

Consider the above example earlier I used to form a differential equation and then do its solution using Laplace,but for this example the differential equation comes out to be non-ordinary. Please ...
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1answer
178 views

Differential equation of a RRC circuit as Voltage output/voltage input?

So in this presentation i have got, there is a RRC circuit, and they get this differential equation, but there is no procedure explained how they have got it. This is basicially a series RRC circuit ...
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3answers
100 views

Difficulty in understanding the paragraph concerning h- parameters

This is a paragraph from "Engineering circuit analysis" by W H Hayt. I really don't understand the statement "it is difficult to open circuit the open terminals...." What does he mean in the paragraph?...
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622 views

Why can RLC resonance be dangerous for electronics

There is a lot of information about RLC circuits and resonance, and many times it is mentioned that when a series (parallel) circuit resonates, a really high voltage (current) can be found across the ...
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331 views

Phase margin Vs damping ratio: Intutive explanation

While designing the compensator for SMPS we always talk about the relation between phase margin and damping factor( or Quality factor). I don't completely understand how damping plays such a keyrole ...
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1answer
186 views

Toy “pull tab”-style feature on PCB

I have recently designed a passive-based modular PCB. When I click the secondary board into the base board, I would like it to break the current circuit at a fixed point, and insert itself in series ...

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