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Questions tagged [resonance]

For questions about resonance, the phenomenon in which the amplitude of an electrical circuit's output increases when the frequency of its input is equal to or near the circuit's natural frequency. Consider also using the "frequency-response" tag.

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Determining transformer equivalent circuit components

I have made a PCB based planar transformer with a turns-ratio of 8:6. I am considering the T-model as shown below: In the T-model, Lp is the primary side leakage inductance, Ls' is the secondary side ...
Jonathan_the_seagull's user avatar
1 vote
3 answers
472 views

Are inductors in resonant circuits dangerous? They produce very high voltages

A simple series LC resonant circuit has theoretically infinite voltage in the middle between L and C, if we assume 0 ESR and exact resonant frequency: \$V_{at LC junc} = V_{in} \frac{X_{C1}}{X_{C1}-...
SRobertJames's user avatar
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2 votes
1 answer
92 views

Will a circuit oscillate at all its resonance modes or only the most dominant one?

Will a circuit oscillate at all its resonance modes or only the most dominant one? Consider an amplifier with a feedback loop that meets the Barkhausen criteria at multiple frequencies. Will it ...
SRobertJames's user avatar
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1 vote
2 answers
136 views

How can this Clapp JFET oscillate when its gate is tied to ground at the resonance frequency?

How does the circuit below oscillate? It seems to have |gain| < 1 at its oscillation frequency of 2.25 MHz, yet it oscillates there. My analysis: The DC path is through L4 only, allowing a bias ...
SRobertJames's user avatar
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5 votes
2 answers
399 views

Where is the phase shift on this oscillator?

I didn't think the oscillator below could work, but I built it, and it does: I used 10 uH for the inductor, 2.7 nF for the capacitor, and got oscillations around 8 MHz. The feedback loop is a series ...
SRobertJames's user avatar
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0 votes
0 answers
33 views

Can transceivers count to fifty resonators? [duplicate]

I asked a since-closed question yesterday about an alternative to RFID. I assumed the way to phrase the question was as the most general possible engineering problem. I infer that it is probably ...
Tom Boardman's user avatar
1 vote
3 answers
132 views

Does this op amp connected to an LC tank amplify its resonant frequency?

The circuit below has a resonant frequency at 159.155 kHz and should amplify it: That's exactly what this sweep predicts: But,even when setting V1 to 159.155 kHz the transient analysis shows no ...
SRobertJames's user avatar
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3 votes
1 answer
99 views

How to digitally detect resonance in induction heater circuit?

System description: H-bridge network of IGBTs (inverter) is used to supply power to a parallel LC circuit connected through matching inductor. It is desired to drive the parallel LC circuit in ...
AR2020's user avatar
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0 votes
2 answers
66 views

Varactor diode simulation behaving opposite than expected

I've been trying to learn about resonance circuits and filters and so forth, intending to try to build some kind of tunable filter or something. I'm running some simulations in KiCAD to help confirm/...
Erhannis's user avatar
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1 vote
2 answers
76 views

Identify values for these resonators

I need some help to identify the values of these resonators. Anyone here have experience with such components?
Mickrige McMahon's user avatar
0 votes
0 answers
25 views

Regarding the equation derivations of the resonant state of an asynchronous buck converter observing zero voltage switching

I'm currently reading this article of Bill Andreycak to understand the mathematics behind zero voltage switching: https://www.ti.com/lit/an/slua159/slua159.pdf?ts=1710666811170&ref_url=https%253A%...
QUEEN SLEAZE's user avatar
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0 answers
25 views

Current/Voltage phase shift issue with low/high capacitor capacitance

How to make voltage/current 90 degree phase shift properly? In my PWM->sine "converter" the current/voltage phase is shifted 90 degree only with low value capacitor (10 uF), but no shift ...
Vadim Ostanin's user avatar
2 votes
0 answers
58 views

Power stage for driving a 100W piezo in resonance [closed]

I'm trying to design a power stage for driving a piezo transducer. It has resonance at about 1 MHz. My system has a DC voltage of 24V. The circuit will be locking frequency based on phase of voltage ...
piotr's user avatar
  • 292
5 votes
2 answers
1k views

Do you know about topologies that look like this?

I'm working on a new topology. I looked it up myself, and it says "3-level boost converter" has a low inductor. Is this right? How do I search it?
kogyu's user avatar
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0 votes
1 answer
79 views

Ironing out a design for resonant inductive coupling on 13A. Would I be better off with MHz or GHz for efficient power transfer?

I am having a go at designing an extension cord that uses resonant inductive coupling. My knowledge lacks in this area, so I'm going back and forth via online research & chatgpt 3.5. From what I ...
Dragonfly3r's user avatar
3 votes
2 answers
257 views

Given that \$Q = {R} {\sqrt{L/C}}\$, why not maximise Q by setting L huge and C tiny?

For the tank circuit below, the resonant frequency is f0=10kHz, where: $$ f0=1/(2 \pi \sqrt{L_1 C_1}). $$ Assuming R=1 ohm, and given that [correction thanks to @Franc] $$ Q_1 = \frac{R} {\sqrt{L_1/...
James V Stone's user avatar
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0 answers
60 views

Brushless DC motor stalls at startup

I have two small fans with brushless 12 V DC motors connected in series. Each motor has a flyback diode. Also in series is a small resistor to bring the voltage down slightly from 28 V, which is the ...
Björn Morén's user avatar
0 votes
1 answer
100 views

4 MHz RF-receiver not working

I have been trying to make a 4 MHz receiver, to receive a ASK/OOK modulated signal but it never really works. I have my suspicions that it's the LC tank that is not tuned correctly, I am quite new to ...
Allfadern's user avatar
5 votes
3 answers
535 views

Multiple resonance frequencies of common-mode choke

In the datasheet of the CMC (common-mode choke) below (Würth Elektronik 744830017132), the impendence vs frequency graph has multiple peaks (resonances) which I marked. The first one is the Self ...
Andr7's user avatar
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4 votes
2 answers
764 views

Please offer comments, critique on self-resonating invented buck joule thief converter for third world use [closed]

Even though I'm not an EE, I have simulated the Joule Thief to death in LTSpice, but I have not yet made a prototype of this circuit. I have a friend who is an EE who won a contract to light some ...
MicroservicesOnDDD's user avatar
3 votes
2 answers
141 views

How is a resonant bandpass filter similar/different from a damped mass-spring oscillator? They seem to behave different in testing

Background I am using resonant bandpass filters as musical oscillators. One can excite an array of them at harmonic frequencies and given Q values for a note by, for example, running a burst of noise ...
mike's user avatar
  • 157
1 vote
1 answer
64 views

External circuit to increase the series capacitance of a resonant circuit

I am working with a long-range reader and antenna coil for a low frequency (135 kHz) RFID application (please see the basic representation below.) The reader features some unknown source impedance, as ...
tomhebe's user avatar
  • 21
2 votes
1 answer
140 views

LC Resonance with Inductor with Solid Metal core

Consider inductor with air gap and solid metal core made from material with relative magnetic permeability 1 regardless of temperature (such as copper or aluminium). There is Air gap between coil and ...
Fan's user avatar
  • 39
4 votes
2 answers
504 views

How can I drive an LC tank with a transistor?

I've been exploring the idea of making an induction heater. Mostly I see people using the ZVS circuit to do it, but I would like to get an understanding as to how you would do it if you had an ADC and ...
TrisT's user avatar
  • 355
0 votes
1 answer
50 views

Why does resonance cause unique behavior of S-param in two-port system?

In a two-port system where a square signal passes through a via we can get a HIGH Q resonance structure which could ruin our S21. I know that resonance is a standing half-wave pattern, so what what ...
Josh23's user avatar
  • 1
0 votes
3 answers
87 views

Why does S-param resonance behavior differ from formula?

The general formula for resonance is \$w_0=\frac{1}{LC}\$ . A simulation was built with such inductor and capacitor so the resonance will be at 1GHZ.However as you can see in the result ,the plot ...
Josh23's user avatar
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0 votes
0 answers
29 views

Why is it difficult to write the close loop transfer function of a frequency modulated DC-DC converter (for eg - LLC converter)?

I know how to derive and write the transfer function of duty cycle/pulse width modulated DC-DC converter. We need to linearize the switches and then write KVL/KCL equations and then derive the output ...
Sudhanva Gokhale's user avatar
0 votes
1 answer
106 views

Why is an LLC converter designed to operate in the ZVS region? how does the Resonance in the LLC circuit contribute to low "MOSFET losses"?

For the first question I understand that operating in the ZCS region can result in shoot through but why does that happen? I understand that an LLC converter uses the leakage inductance of the ...
Sudhanva Gokhale's user avatar
1 vote
3 answers
419 views

What is the difference between natural frequencies and resonance frequency in second order circuits?

The following circuit: can be described by: $$\frac{d^2v_c}{dt^2} + \frac{R}{L}\frac{dv_c}{dt} + \frac{1}{LC}v_c = \frac{R}{LC}i_S$$ From there, it's clear that the undamped natural frequency, or ...
Dan's user avatar
  • 145
0 votes
2 answers
210 views

LC Parallel resonance induction heater

Consider parallel LC resonance induction circuit with solid iron workpiece, inserted in the inductor. Is it possible to obtain more heat power output from the heated solid iron workpiece in the ...
Fan's user avatar
  • 39
0 votes
1 answer
69 views

Power supply coupling of inductive resonant sensors

I'm working on an array of sensors based on Peltz Oscillators connected to a micro to detect objects based on shifts in resonant frequency when a target object gets close to the inductor. In isolation,...
learnvst's user avatar
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3 votes
0 answers
135 views

Resonant Coupling for Optimal Power Transfer

I am trying to read the following paper: B. L. Cannon, J. F. Hoburg, D. D. Stancil and S. C. Goldstein, "Magnetic Resonant Coupling As a Potential Means for Wireless Power Transfer to Multiple ...
ELec's user avatar
  • 31
1 vote
1 answer
489 views

How can I find the Q factor an LC circuit using LTspice?

I've built a very simple LC circuit which models a air core copper wire loop antenna. I got the circuit resonate at around my desired frequency i.e., 13.56 Mhz. Now I want to calculate the Q factor ...
Hako's user avatar
  • 11
1 vote
1 answer
243 views

How to choose power rating of a damping resistor for an LC filter? [closed]

I am trying to put power filter for an SMD oscillator (https://www.renesas.com/us/en/document/apn/863-power-filter-recommendations-smd-oscillators). One concern is the LC resonance. There are ...
jsmith's user avatar
  • 669
0 votes
0 answers
99 views

Calculating inductance of solenoid using a resonant RLC circuit

I tried to perform an experiment in my school physics lab with an RLC circuit. I plotted the variation of the voltage across the resistor against the frequency of the source. From the figure below, it ...
Shreya Anish's user avatar
1 vote
0 answers
100 views

Resonant circuit in class C amplifier

Questions What is the better option when maximum efficiency of class C amplifier is needed: LC circuit between VCC and drain of amplifier + low pass filter RF choke and low pass filter simulate ...
piotr's user avatar
  • 292
6 votes
3 answers
564 views

LM337 Unstable regulation

For an audio project, I need a low noise +/- 12V supply. I have a linear power supply of +/- 15V and I decided to use the LM317 and LM337 to decrease the voltage to 12V. The circuit that I use is the ...
Kostr's user avatar
  • 73
0 votes
2 answers
308 views

Understanding my basic parallel LC circuit, theory vs results

I made a basic LC parallel circuit. 2.9 µH inductance (measured with a cheap meter) 560 nF capacitor in parallel following f = 1/((2pi)sqrt(LC)) it should resonate at 124.89 kHz, but was manually ...
cj91's user avatar
  • 155
0 votes
1 answer
186 views

One port resonator critical coupling Q factor measurement using S11 [closed]

I saw this youtube video which says there are two methods measuring unloaded Q factor. He says there are two options as shown bellow. I have a one port resonator. I could not find anywhere the theory ...
lub2354's user avatar
  • 373
1 vote
1 answer
578 views

Zero Voltage switching

I am having confusion regarding the understanding of Zero Voltage switching as given in the website. What does the ZVS do in the circuit shown below? Does it produce a sine wave or it just makes the ...
kam1212's user avatar
  • 669
2 votes
2 answers
149 views

Confusion About Anti-Resonant Impedance

I am in the process of investigating a crystal oscillator for a design, and I've been refreshing my understanding of resonant circuits. I've closed most of the gaps in my knowledge, however I am ...
Tristan Lee's user avatar
0 votes
1 answer
62 views

Resonance inverters and pulsation frequency

I was reading one of the patents for the x-ray generator when I found a resonance inverter attached in front of the switching circuit. I understood how the system works but one statement written is ...
kam1212's user avatar
  • 669
1 vote
2 answers
131 views

Unstable oscilloscope reading in LC Tank circuit

I'm very new to LC circuits and signal generators but I would like to learn more about them. I have a capacitor which I do not know the exact value. But it is in the range of pF. Therefore I decided ...
Edgy Current's user avatar
1 vote
1 answer
160 views

Piezo sensor at resonance - equivalent model

piezo materials are commonly modelled with the BVD model When the piezo is used as a sensor, they are commonly modelled as a current source in parallel with a capacitor because à external force ...
nohu42's user avatar
  • 31
0 votes
1 answer
195 views

Struggling to work out initial conditions for LC circuit

If we have a inductor and capacitor in parallel, then from what I can tell, the equation for the current is just the simple harmonic motion equation: i = Acos(w0t) + Bsin(w0t). However I am struggling ...
Bren's user avatar
  • 45
0 votes
2 answers
578 views

How to find lossy parallel LC tank Q factor, bandwidth, and half-power-frequency?

Ideal parallel LC tank has infinite impedance at resonance frequency. However, real components, especially inductors, have unignorable ESR, causing ideally infinite impedance dropping to a finite ...
Willis Lin's user avatar
0 votes
1 answer
193 views

Why it is oscillating? is this self oscillation? how to remove

Hello i have an circuit (2 stage op amplifier) with an resonance coil on input. I give an impulse on the coil and the circuit start resonating at frequency 1khz for seconds. How i can change the ...
Viacheslav Popika's user avatar
1 vote
1 answer
249 views

What is the resonant frequency?

I know the formula of resonance frequency for both series and parallel circuits. But when we have a circuit that is shown in the image below where the RESISTOR and INDUCTOR are in parallel and their ...
RK Eshat's user avatar
  • 153
0 votes
1 answer
56 views

Phase velocity expression

We have a \$\beta l\$ expression which is represented as phase velocity. I know \$\omega_o=2\pi f\$. What is the exact expression for phase velocity used in here?
lub2354's user avatar
  • 373
0 votes
1 answer
123 views

Does a Tesla coil's secondary parasitic capacitance and top load capacitance add up?

I came to this question recently and suppose it's true that the secondary's parasitic capacitance does indeed add up with the value of the top load's capacitance, but I really want to hear someone ...
Roman's user avatar
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