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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2answers
304 views

RLC Impedance Calculation

Sorry, will provide more information now. I am working through this question from an all about circuits webpage (See attached webpage link) and have having trouble seeing how they calculate an ...
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1answer
56 views

How is the sweep type affecting the Bode plots for the same AC analysis in LTspice?

When I do an AC analysis for the following circuit between 0.1Hz upto 20MHz, and by selecting "decade" in sweep types I obtain the following plots: But if I do exactly the same thing only this time I ...
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2answers
54 views

Source transformation violation

Using thevenins or norton theorem, we can easily find current through the resistor as 1 amps. But if we convert the current source to voltage source , current turns out to be zero amps . Why?
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1answer
82 views

Confused with electrostatic pickup and capacitive coupling terms

I can understand the meaning of capacitive coupling of the signal line to GND or Earth or nearby earthed objects. Below line section illustrates that: But there is also a term called “electrostatic ...
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2answers
783 views

Analysis of an LC circuit antenna

I want to analyse a parallel LC circuit in terms of inputs and outputs as I am studying them in the context of using them as a tuned antenna. However I am unsure of where to identify the inputs and ...
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2answers
146 views

Reset circuit loops forever on-off

I've designed the following circuit: This is a "self-reset" circuit, VCC_IN es 12V from source, VCC_OUT powers the entire board, including a PIC microcontroller. The idea behind this is whenever the ...
2
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1answer
597 views

RL circuit: How to determine the equivalent resistance of the circuit?

So I'm working on an RL circuit and the solution is stated to be that R1 and R3 are in series, but I didn't think that was the case because they don't have the same current through them. Given ...
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1answer
537 views

Differential Equation of a LC Low Pass Filter

I'm trying to learn about different applications of RLC circuits and have been presented with a weird looking circuit... I've only ever dealt with circuits that can be modeled with a 2nd-order ...
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1answer
154 views

finding small R in series RLC circuit

Hello! I have an device which is equivalent circuit is RC as follows in the image I shared: R is supposed to be 0.5Ω and C supposed to be 30nF, but it can vary a little bit between device to device. ...
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2answers
465 views

How to experimentally measure damping in RLC circuits?

I know there are methods to theoretically determine the damping factor and quality factor in RLC circuits. Equations such as $$\zeta = \frac{R_s}{2} \sqrt{\frac{C}{L}}$$ $$Q = \frac{1}{2\zeta}$$ ...
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1answer
190 views

Neglecting certain elements in deriving the current of a series RLC circuit

The current at resonance in a series RLC circuit is described in the bottom derivation, along with it being plugged into the formula for finding the voltage across the inductor in the circuitw: I ...
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1answer
234 views

RC-LC network equals lowpass filter of third order?

As far as I know only this are two lowpass filters (R-C1, L-C2) of order 1 and 2 respectively. Is it possible to denote this circuit as Low-pass filter of third order? Or is it possible to transform ...
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2answers
161 views

Eliminating the resistance variable in the total resistance/reactance equation of a series RLC circuit

Assuming that we have a simplified equation from a simple series RLC circuit where the total resistance/reactance in the series RLC circuit is equal to 100 times the resistance R: How do we modify ...
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1answer
658 views

Building a series RLC circuit using a given resonant frequency and bandwidth value

Assuming that we have to build a simple series RLC circuit in such a way that the its resonant frequency must be 200 krad/s and its bandwidth as 20 krad/s, we have these components: Resistor: 1000 ...
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1answer
72 views

How do I determine the unknowns for this equation?

Suppose a series RLC circuit in series with a 12 V battery and a switch initially opened. R = 100 Ω, L = 100mH and C = 10uF. L and C are initially discharged. A t=0 the switch is closed. I want to ...
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1answer
277 views

What is the meaning of current at infinite time for a series RLC circuit formula

I am reading this doc. At one point, the author says the current equation form a critically damped series RLC circuit when a step function is applied is: \$ I_L(t) = I_{\infty} + (B_1 + B_2t)e^{-\...
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1answer
297 views

Series and Parallel RLC Circuit [closed]

I am trying to build a resonant circuit for data communication between coils. Which would be better, a series or a parallel resonant circuit? What is the difference between them and in which ...
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1answer
405 views

Why is resistor in parallel with capacitor needed in capacitor bank?

Capacitor bank in power supply compensates for when input voltage is shortly disconnected (50ms lets say). Do capacitors in this setup (between input and the output of power supply), get initially ...
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1answer
61 views

Finding the unknowns of a current equation leads to non-sense

Suppose a series RLC circuit that is critically damped. Circuit is RLC in series with a DC voltage source \$ V_S \$ and a switch initially open. Capacitor and inductor are both discharged. at t=0 ...
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1answer
50 views

How do I calculate the unknowns of the current equation for a RLC series circuit?

Suppose I was dealing with the following voltage equation for the RLC series circuit: \$ v(t) = Ae^{m_1t} + Be^{m_2t} + V_s \$ To know the values of A and B I would do the two initial conditions: ...
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1answer
62 views

Trying to solve a RL circuit by hand but simulator calculates a value I do not understand

I have this circuit. V3 is just a trigger to close the switch, just ignore it. The switch is open for a long time. So, the left part of the circuit is working for a long time and the inductor is ...
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3answers
411 views

Why is the inductor necessary in an LC filter?

I am using an LC filter for the output of a buck converter. Dont both the inductor and capacitor just attenuate high frequency signals? Does having the inductor affect the output voltage or does it ...
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0answers
72 views

LC oscillator emitter current doesnt go to 0(class C)

Im trying to create a 433MHz oscillator with the help of ADS for the simulation. From the lectures i have had on transistor LC oscillators, i know the are forced into class C operation, and that ...
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2answers
433 views

State Space model for three-loop circuit

How do I choose the least number of state variables for the following circuit? I started out by assuming currents $$i_{1}, i_{2}, i_{3}$$ in each of the loops and applied KVL, which fetched me three ...
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1answer
68 views

Trying to understand the magic the author of this PDF did explaining the critically damped equation

I am reading this doc about the equations for the step function for the RLC circuit, critically damped solution. At page 16 we have these lines... But there is a magic between these lines... How ...
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1answer
69 views

Bounds of impedance matrix of a passive two port network

If we consider the impedance matrix of a linear, reciprocal passive network (Z12 =Z21 because of the reciprocity), $$ \begin{bmatrix} Z_{11} & Z_{12} \\ Z_{12} & Z_{22} \...
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3answers
110 views

What value of C should be added in parallel to make the circuit appear purely resistive?

I'm currently working through Cogdell's Foundations of Electrical Circuits and came across problem 4.39 d) as shown below: Earlier in the question I found the frequency-to-be-used as 43.3x10^3 rad/s. ...
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2answers
99 views

Trying to understand why the signal was inverted on this RC step response equation

I am watching this video where the guy is deriving the equations for the step function of a series RC circuit. At some point he has the following equation: \$ \frac{dt}{RC} = \frac{dv}{v_s - v} \$...
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3answers
469 views

RL-C Circuit Problem

I am trying to get some practice on the basics, but i am having some issues with the following question: Find Currents I(1) and I(2) and show them on a phasor diagram. Find the total current, I(total)...
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1answer
60 views

Trying to understand the transient current equation on a RLC circuit

I am reading this doc I see this magic happening on the third line of equations... How in the name of Math, does this \$ Ae^{st} \$ appeared there? Magic?
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2answers
182 views

What is the impedance in a theoretical LC circuit?

While writing a paper about an experiment I am conducting, I was wondering how inductor-capacitor circuits theoretically behaved. In theory, we assume that wires and components that are not resistors ...
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1answer
27 views

Unsuccessful when testing a power entry module model in simulation

I'm trying to understand how this power entry module suppresses common mode interference. Here is the diagram: I want to sort of make a simplistic EMC test in simulation just to see how the common ...
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2answers
62 views

Trying to understand the critically damped equations of a RLC circuit

I am trying to understand the equations of the critically damped equations of a RLC circuit here I see this part on page 16 The part I do not understand is this one: How can part of the equation be ...
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2answers
237 views

How to choose current sense resistor and current sense Amplifier for precision sensing

While measuring current from 0A to 500mA with 10uA step, I am using current resistor, current sense amplifier, 16-bit ADC.How do I choose current sense amplifier and current sense resistor
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0answers
168 views

Question on inductors with initial current

Question: Initially the switch position is aa', 3 H is connected across a 3 A supply and 6 H is connected across 6 A supply. After some time the make before break switch is actuated to the new ...
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2answers
55 views

Transmittance of a capacitively coupled shunt resonator

I have been trying to understand the expression of |s21| for the resonator mentioned in this article. For a circuit similar to the drawn below, in which R1 is used as the temperature sensitive element,...
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2answers
154 views

Why exactly a RLC Circuit powered by DC oscillates?

First sorry if the question is stupid... I am learning. I am trying to visualize here, without equations, what happens to a RLC circuit that makes it oscillate. Consider a RLC circuit, a switch and ...
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2answers
196 views

Simulating all transient solutions for RLC series circuits

I am reading this page that contains the transient solutions for RLC series circuits: over-damped, critically damped and under-dumped. This site presents these graphics for the 3 cases: Then I have ...
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2answers
145 views

Capacitively coupled shunt resonator

The diagram below shows a capacitively coupled parallel RLC resonator. Through simulations I observe that C2 and C3 influence the resonant frequency . I'd like to obtain the analytic expression for ...
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0answers
170 views

LC filter stepper motor

can i use lc filter on three phase stepper motor (variable reluctance motor) to get sinewave current ? We know that if we put sinewave voltage on ststor windings, the stator current will not be ...
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3answers
125 views

Volt/Amp dependent RLC band pass -> Loudspeaker expander using lightbulbs

I want to create a input energy dependent frequency shunt network, which goes in parallel with a loudspeaker, At low volumes, a certain midrange frequency should be shunted off the loudspeaker. The ...
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3answers
413 views

Why do we use Laplace transforms to analyse transient circuits?

I just learned transient circuits and we solved them both in the time domain and the Laplace domain and I can't understand why we would use the Laplace domain as it seems it is a lot more simple to ...
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3answers
538 views

How is this circuit providing solution of the differential equation d^2 v/dt^2 = -9v?

Book pages at https://books.google.co.in/books?id=d-7owi6uNtMC What I see is that they have taken d^2 v/dt^2 as an input at point A, integrated it to get dv/dt, integrated it again to get v=2sin3t V,...
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1answer
228 views

Parallel RLC tank transfer function

I have seen the expression for the transfer function of an RLC tank given as the following. $$H(j\omega) = \frac{H_o}{1+j2Q\frac{\omega-\omega_o}{\omega_o}}$$ I am somewhat able to get this result, ...
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1answer
109 views

Close Oscillators Problem

I have 3 "Emitter-Coupled" Oscillator, the difference is that I don't use a resistor on the tank circuit and I do vary the Inductor inductance. They're close on the PCB and they got some disturbs, if ...
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1answer
239 views

What is the use of a RLC circuit placed before a full bridge rectifier?

While analysing a PCB, I realised that a RLC circuit was placed before the full bridge rectifier. I am wondering, what functional use does it have? simulate this circuit – Schematic created ...
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4answers
1k views

Why is a linear passive circuit stable, i.e. why does its impulse response approach zero over time?

This is a silly question to ask because the answer might be obvious, but I still have my doubts. If given a circuit composed only of resistors, inductors, and capacitors, if its impulse response ...
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2answers
92 views

In series RLC circuit, does increasing capacitance value really make the circuit more inductive circuit?

This seems very counter intuitive to me. How can increasing capacitance value make the circuit more inductive ? The math tells me so : If \$C\$ increases then \$X_c = \dfrac{1}{\omega C}\$ decreases,...
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2answers
180 views

Network theorem Source Transformation

When i am using Superposition Theorem i am getting 80W but when i using Source transformation getting 0W.Why getting different answers? Is there anything Hidden in source transformation that I need ...
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0answers
26 views

How does the change of load on the Rx side influence the Tx resonance voltage in a wireless powering sysytem

As the circuit shows, U = 5V toggling the polarity in 10KHz. When IL is changed from less than 1mA to 20mA, the P-P voltage of the Tx coil will increase. How should I understand the phenomenon? I have ...

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