# 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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64 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 ...
1 vote
60 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 ...
398 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 ...
112 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 ...
34 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 ...
1 vote
105 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 ...
91 views

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 ...
43 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 ...
1 vote
64 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 ...
1 vote
35 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 ...
57 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 ...
129 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 ...
112 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 ...
21 views

### Good coupling intuitions between microstrip line and cylindrical dielectric resonator

I am trying to get a good coupling between microstrip resonator and cylindrical dielectric resonator. I know it's a sort of transformer equivalent model. I am moving the dielectric cylinder around the ...
1 vote
90 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 ...
53 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?
36 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 ...
644 views

### What is the frequency at which a series RLC circuit stores maximum energy?

I was reading about the quality factor of a series RLC circuit. The quality factor is defined as $$2\pi*\frac{\text{maximum energy stored}}{\text{total energy lost per period}}$$ Here maximum energy ...
562 views

### Simulating a tuning circuit in LTspice

This is the tuning circuit that I'm trying to simulate in LTspice: My input signal is the sum of a 500 kHz, 1 MHz, and 1.5 MHz sine wave, all modulated at 5 kHz. The 5 kHz waves carried by each of ...
240 views

### How does a microwave oven transformer shunt help resonate the voltage doubling capacitor?

I was reading this great answer by Neil_UK, and a comment-question was: Comment Question 1 Are MOTs belonging to the general type called "Leakage/stray field transformer" ?en.wikipedia.org/...
33 views

### LLC convert design misunderstood

The question is addressed to those who have designed LLC converter. As you you know during the design steps you come to graphs that looks like the uploaded one. The intuitive view is when you ...
60 views

I have selected all my components except for the resonant capacitor. 1uF C0G MLCC is hard to find where I live. I checked almost every component distributor website but no results. I want to know how ...
36 views

### LLC working above resonance

I am designing LLC Half-Bridge converter: Pout = 500W, Out = 12V, Vin = 390V, Fr = 80kHz, Lr = 30 uH, Cr = 120nF, Lp = 190uH The converter is working always above resonant frequency. The ...
70 views

### How can I solve these two equations to determine resonant capacitors for a wireless charging coil?

My questions: What are S, D, and the apostrophe above Inductance? Is the equation looking for the inductance of the coil or the circuit? Once I know what S and D stand for how can I determine their ...
1 vote
87 views

### How to calculate the capacitance needed to reduce oscillations in this circuit?

The following circuit is part of a DC current driver for a Helmholtz coil (L2,RL2), the circuits for Vreg and Vin work as intended so I am pretty sure that the oscillation is coming from this side of ...
126 views

### If the impedance of two coils is measured to be identical at 250.0 kHz, is it safe to assume identical impedance across the spectrum?

This question pertains to matching two air-gap inductors for use in resonant coupling. Alternative solutions are welcomed and appreciated. The two coils shall be comprised of identical wire. The two ...
30 views

### Help in understanding resonance in 1/4 wavelength detector / S parameters

So this might be long question that requires some literature review but I will try condense it as much as possible such that hopefully I can get some help without the reader having to review the ...
1 vote
130 views

### 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 ...
261 views

### How does resonance lead to an increase in the overall voltage? [closed]

How exactly does resonance lead to an increase in the overall voltage greater than that of the supplied voltage?
75 views

### High Frequency Oscillations on Mosfet Gate

I am working on a circuit that drives an inductor at its resonant frequency. However certain models of MOSFET I simulate the circuit with experience oscillations at the MOSFET gates as pictured below. ...
1 vote
89 views

### How do I model an RF coil in SPICE?

I am trying to model a transmit/receive RF coil in SPICE - specifically, a coil that one might use on an NMR spectrometer. Put simply, the RF coil detects an EMF per Faraday's Law of Induction, by ...
1 vote
93 views

### What is wrong with my charge-transfer balancing circuit for a Li-ion battery?

I am trying to simulate this balancing circuit. The two complementary pulses control MOSFETs and as the resonant tank works the capacitors(as batteries) start to balance and I used op-amps to measure ...
1 vote
49 views

### Does anyone know a feedback circuit (or IC) for doing a high voltage resonance sweep?

My team and I are designing an induction heater, and I've been asked to look into resonance sweeping so the microcontroller controlling our application can automatically find the resonant frequency. ...
1 vote
77 views

### Parallel RLC circuit doesn't produce expected results in Multisim

I am trying to create AC from DC. My device is based on the transient response of a parallel RLC circuit: simulate this circuit – Schematic created using CircuitLab If there is some energy ...
3k views

### Why do these two sets of seemingly identical capacitors behave differently?

I have two sets of almost identical-looking capacitors which show different behaviour: The ones on the left (which are definitely these MLCCs) act as I would expect, but the ones on the right (which ...
166 views

### How to determine parameters for the Resonant Royer (or Baxandall) circuit?

I'm learning about the Resonant Royer circuit (or Baxandall circuit). There is a picture from the wikipedia(Royer circuit): Or if you like, you can see my simulation. I learn about how it works from ...
161 views

### Resonance in AC circuits

Derive the frequency for resonance condition in the following circuit. My perception is that I need to nullify the j part of equivalent impedence, is that correct? Question: My approach:
55 views

### Will a nuclear magnetic resonance (NMR) or magnetic resonance imaging (MRI) impulse blind our signal response sensor?

After we send an impulse to the coil, when we start read the coil will have self oscillations. What influence will the self oscillations have on the read response? How can we deal with the self ...
1 vote
71 views

### Circuit simplification containing transmission lines, assuming a high quality factor

I am trying to digest the paper of M.S Khalil et al. 2012(1) on asymmetric resonator transmission (in superconducting devices). In it, early on, a resonator circuit coupled to a transmission line is ...
56 views

### Reducing temperature of the Rx coil in a wireless power transfer circuit

I have currently designed a wireless power transfer circuit which is based on the ZVS principle and Royer circuit. The issue I am currently facing is that the receiver coil is warming up a fair bit, ...
63 views

### Is a microwave's cooking cavity of particular dimensions according to the characteristics of the input microwave feed?

i.e. if I were to connect the magnetron inside my microwave to a slightly different steel box (see pic) of a different size and shape (provided the volume inside was roughly similar to the one in my ...
64 views

### What is causing this resonance point in my S11 Trace?

Does anyone know what is causing the higher frequency occuring in the S11 trace of this simulation? I have checked all the capacitances and inductances associated with the transformer and ...
62 views

### Parallel Resonance for Wireless Power Transfer

I have two 50 uH coils. I'm using a 68 nF capacitor for each the primary and secondary coils. This puts the resonance frequency to about 86.313 KHz. The primary coil is in series with the 68 nF ...
1 vote
68 views

### Resonance Frequency Drift

I'm working on a wireless power transfer project. The coils that I'm using are made out of Litz wire with a value of 50 uH. For the capacitors, I'm using 68 nF capacitors. This puts the resonance ...
253 views

### Why doesn't the voltage at the resonance frequency go above the input frequency of a sine wave source?

I have performed a simple RLC parallel circuit experiment to determine the resonance frequency. I used the voltage as the magnitude. Experimentally, the magnitude at the resonance frequency tops at ...
68 views

### what voltage rating do I have to observe at resonant frequency?

This is the schematic of the resonant switched capacitor cell balancing circuit. The problem is that at the resonant frequency when the capacitor and inductor impedances become equal and the total ...
75 views

### Electron flow in LC circuit in resonance - why capacitive reactance reduces inductive reactance to zero (by intuition)

I understand why capacitive reactance reduces inductive reactance mathematically, having a result of zero at resonant frequency. But how to physically explain the flow of electrons in series LC ...
52 views

### Resonant frequency of a tuning circuit with varactors

This is the circuit that I'm simulating in LTSpice: I measured the experimental resonant frequency of the circuit by finding the frequency at which $V_\text{out}$ peaks for different values of \\$...