# Questions tagged [resonance]

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1answer
63 views

### Can someone help me understand the exact working of this configuration of a Colpitt's oscillator?

So I came across this Collpitt's oscillator in a research paper that I am thinking of implementing but it looks quite different from other configurations and I would really appreciate some help ...
0answers
44 views

### Control of a resonant capacitor

I am working on a data transmission system. For the data signal to be fully amplified, I want the circuit to resonate. I would like the signal to be already fully amplified across the inductors and ...
0answers
38 views

### Wireless power transfer - 6.78 MHz resonant circuit

I work on wireless power transfer. I used (EPC9065: High-Frequency ZVS Class-D Power Amplifier) I have a resonance circuit series-parallel topology work on 6.78 MHz, when I connect the circuit and ...
2answers
36 views

### How do I see the resonance of a high-impedance coil with a VNA?

When it comes to measurements with VNA, my experience tells me that whenever there is a "dip" in the S11 parameter, your takeaway should be that there is a resonance there (this is how the ...
1answer
106 views

### Finding resonant frequency or damping ratio from Bode Plot

I am working on a question where I have to estimate a transfer function from its bode plot. I plotted the asymptotes of this bode diagram, and was able to find out that this is 3rd order system with ...
1answer
58 views

### Crystal frequencies

the context is that I am working on project which uses a 32 768 Hz quartz oscillator used for a uC. My questions are: I have read that series resistance should be low (25 to 100 Ohm) otherwise it can ...
3answers
188 views

### Wien Bridge Oscillator: Why does equating the real part to 0 give the gain equation?

I am learning about Wien bridge oscillators. Following Experiment No. 9: WIEN BRIDGE OSCILLATOR USING OPAMP, they use the following schematic: They then arrive at the following equation half-way down ...
0answers
63 views

### Two resonances in the admittance of capacitor C

I have this question that has been haunting me for a week now. I was given a measurement file of a previous student. Allegedly, they are the measurements of the admittance of a circuit that is ...
1answer
29 views

### Quality factor multiple definitions

On studying RLC circuits, I have come across two definitions of Q factor. One is obviously the measure of selectivity and goes as this: The other is this: Is there any link between these 2 ...
4answers
905 views

### Definition of RLC resonance frequency

I have found that a commonly mentioned definition for the resonance frequency in an RLC circuit is defined as the condition where the capacitive and inductive reactances cancel each other, resulting ...
3answers
63 views

### Single value capacitor or two different in parallel for filtering the power supply for microcontroller

I am trying to design power supply for the STM32F446 for my PCB. I wonder if I should stick to the Datasheet of STM32F446 Page 71 and use two capacitors or be careful about it and maybe just use one ...
0answers
49 views

### How can I play midi on this tesla coil?

I've made several small tesla coils, however I wanted to buy one that was compact and powerful, so I bought this one. I'm assuming it is a drsstc, since it has a half bridge of mosfets or igbts, which ...
4answers
112 views

### Resonance Frequency of system with two inductors

I am trying to derive a formula for the resonance frequency of the following circuit: The piece that is giving me trouble are the two inductors, that (although I might be wrong) cannot be further ...
0answers
61 views

### LC series circuit resonance beyond voltage limits of programmable capacitor - solvable with gain stage?

I am replicating a design where a mechanical tuning capacitor is in series with an inductor antenna, in order to achieve resonance at certain (hundreds of kiloHertz) frequencies. I am looking into ...
2answers
63 views

### Crystal radio receiver

Why is a parallel LC circuit used to filter out the right frequency from the antenna? Shouldn't it be in series? We have a maximum impedance at resonant frequency if we connect in parallel, so why isn'...
0answers
47 views

### Design for a PLL Auto-Locking Circuit

I am looking into electrolysis efficiency using an auto-locking PLL circuit that is supposed to latch onto the resonant frequency of the electrolysis cell, a frequency determined by the inductance of ...
2answers
72 views

### Frequency that quartz crystal can handle

I understand that when an applied voltage signal enters the quartz crystal, it mechanically vibrates. Now, let's say that the voltage is 1 kHz and the quartz crystal is 32.728 kHz, can the quartz ...
1answer
212 views

### Why can generators be damaged by series capacitors (SSR)?

Specifically I am talking about generation that uses steam to generate turbo spin (steam cycle) like nuclear or natural gas plants. I have been learning about Subsynchronous Resonance (SSR), which is ...
1answer
86 views

### Resonant frequency of RLC circuit

Analysis I'm trying to find the resonant frequency for this circuit simulate this circuit – Schematic created using CircuitLab Writing up the node voltage equation for $V_o$ \frac{V_o-V_{...
1answer
59 views

### Reducing resonance in a piezoelectric ultrasonic transducer

I am using a piezo transducer to launch an ultrasonic pulse in air, at a frequency of 125kHz. A picture of the received waveform is attached. My question concerns how I can (electronically) limit the ...
2answers
65 views

### Increase input current in series resonant circuit

I have an antenna/coil for an RFID application that I am resonating with a series capacitor. However, the current remains extremely low and does not agree with the calculated/theoretical values for ...
1answer
44 views

### High power factor but maximum current at resonance in series RLC circuit

In a series RLC circuit, at resonance, the power factor is unity but the current is high. But since in high power factor the current drawn is low, then isn't this a paradox? High current is ...
1answer
95 views

### Impedance in LTspice and current plotting

I wanted to try a test simulation on LTSpice to understand few things. I have a RLC parallel circuit and I wanted to see how the impedance varies according to each one of the components (very easy but ...
1answer
67 views

### A question regarding the resonant circuits

I am at the beginning of trying to understand resonant circuits, so after doing some research about the basic of resonant circuits , I noticed that there are diagrams appearing the basic working of a ...
4answers
2k views

### Ceramic resonator changes and maintains frequency when touched

I'm experiencing a weird phenomenon with a ceramic resonator test circuit, where the frequency of its output can be changed by touching the circuit with my finger. The circuit would maintain this ...
1answer
64 views

### How can a resonator do band-pass filtering?

I've read many times some statements about resonators like this (reference): Resonant circuits are circuits, which offers a high impedance or low impedance (for parallel and series resonance ...
1answer
51 views

### Parallel LC circuit Q factor inductance role

I'm wondering why Q factor in parallel LCR circuit is proportional of C and inversely proportional to L according to the formula $Q = R \sqrt{C/L}$ completely lost here
1answer
127 views

### Induction heater resonance working

I was reading this article on the working of a induction heater. The below is a circuit show in the article which I was not able to understand. I have 3 questions : I think that Vsupply is a ...
1answer
84 views

### Tuned common emitter amplifier design

I am trying to learn electronics with the help of the Art of Electronics From Horowitz and Hill. I am working on transistors and amplifiers and I am currently working on problem 2.16: Design a tuned ...
1answer
40 views

### The equivalent inductance of a RLC in parallel

When studying a system that has the same behavior of an RLC parallel circuit, the slope of the impedance before the resonance corresponds to the value of the equivalent inductance, the slope after the ...
1answer
75 views

### Resonance frequency of a system

I have a small problem with my LTspice simulation... When you have a system that contains multiple capacitors, inductors and resistors, how do you know, when you measure its equivalent impedance Z ...
1answer
77 views

### LTSpice AC analysis and DC analysis don't agree?

I have a simple circuit pi circuit. When I do the math and subsequently run the simulation on LTSpice, I get a similar answer - the resonance occurs at f= 217447Hz (math), 217450(LSpice). The error ...
0answers
78 views

### Why does the LLC converter have an Lm inductor? How does it interact with the LC circuit?

Task: to understand why the LLC converter has Lm inductance and how it interacts with the LC circuit. What I learned: LLC converter circuit: The LLC converter is a DC to DC buck converter (...
1answer
99 views

### What is the explanation of non-zero VCE voltage of an IGBT while its gate is high?

While investigating a malfunctioning high power induction heater system (which constantly destroys its IGBT modules), I came across an interesting situation. Circuit Gate drivers are SKYPER 32 PRO R ...
3answers
88 views

### Why does a Tesla coil secondary need intermittent excitation to achieve resonance?

I have been reading about Tesla coils and their principle of operation - if I have understood correctly - after the primary is sufficiently charged, its circuit is closed (by means of a spark gap or ...
0answers
46 views

### Absolute values of fourier transform of noise-charged RLC circuit

I am doing time-domain simulations of currents in a parallel RLC circuit charged by thermal noise. In detail in pseudo-code: ...
0answers
46 views

### Resonance frequency of a circuit

I have a question concerning the resonance (or anti-resonance) frequency of a circuit. Will taking into account frequency-dependent behavior of the passive components change (skin and proximity effect ...
1answer
84 views

### Does the type of preamplifier used for a piezoelectric sensor change its physical resonant frequency?

Two common amplifier circuits used for piezoelectric sensors are voltage amplifiers and charge amplifiers (pictured respectively). With the charge amplifier, the sensor is shorted but this is not the ...
1answer
48 views

### Question regarding the working of slightly different oscillator topologies

I tried simulating two slightly different versions of the Colpitts oscillator in LTspice. Here is the first one: This circuit oscillates at 53.8Mhz. It is quite easy to understand how this circuit ...
0answers
80 views

### Analytically understanding wireless power transfer

https://youtu.be/M8aZoM9p43k This YouTube link shows a experiment I quickly made. Two resonant lc circuits that use magnetic fields to wirelessly light up a led. I manually found the best frequency ...
0answers
35 views

### Resonant frequency of a three phase thyristor rectifier

I am trying to inspect how my circuit behaves at operating points around resonant frequency. Is resonant frequency simple equal to 1/(2Pisqrt(LC)) = 1/(2pisqrt(590uH240uF)) = 423 Hz (see the circuit ...
1answer
46 views

### Degradation of resonant sine wave signal in coil/solenoid after adding second layer

I have hand-wrapped a couple of air core tube coils/solenoids with 50 gauge wire (0.001 inch diameter). My goal is to obtain a resonant frequency of ~10 khz without the use of a capacitor and to keep ...
0answers
74 views

### How to select an inductor for 3rd overtone oscillator SIMPLIFIED way

My question is at least approximate calculation of L1 inductor. With my design I have followed below SIMPLIFIED rules. Can someone correct any of my mistakes, if my component selection is proper? ...
1answer
80 views

### Find the Q-factor for coils and understand weak power transfer

I built coils for wireless power transfer. Found inductance with a LRC meter. Put capacitors, hoping for a resonant frequency at 300kHz. Student assisted me with a NVA machine where a resonant ...
1answer
77 views

### Colpitts Oscillator

I am implementing the following oscillator circuitry on my breadboard: I am using the LM324n op amp and a solderless breadboard. The oscillator is tuned at about 500KHz resonant frequency, but when I ...
1answer
101 views

### Non linear behaviour of a pure LC: Is it real or LT Spice is broken?

Questions: 1) Is the observed behaviour correct? (both cases at the resonant frequency and at a lower frequency) If it's not correct, why LT Spice is giving this result? 2) Why does circuit lab give a ...
1answer
80 views

### Wirless Power Tansfer Circuit

Hello so my university is closed because of covid. I am allowed one day into their labs to build and test my WPT device. My Tx is very large compared to my Rx. I have tested their inductance with a ...
1answer
238 views

### Resonant Q Factor vs Voltage Gain

I was pondering the analytic effect of Q on the voltage gain for quarter wavelength helical resonators (Tesla Coil Secondary). One of the reasons a great looking secondary can perform poorly is due to ...
2answers
53 views

### Resonant frequency and maximum signal width

I've seen resonant frequency being defined as the point where the input signal is in phase with the output signal (So reactance/susceptance is 0). However conceptually, teaching material seems to link ...
3answers
69 views

### LC receiver - resonance frequency

I am building simple LC receiver. I have to use a 30 mH coil and "catch" 30-40 kHz frequencies. By my calculations I need to use +- 800 pF capacitor. Unfortunately I have only 100 pF ...