Questions tagged [resonance]

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18
votes
7answers
9k views

LC circuit, bigger L than C, or bigger C than L?

So if I want my LC circuit to resonate at 20MHz, I just use the formula, \$F=\frac{1} {2\pi\sqrt{LC}}\$. Using available inductor and capacitor values, there are lots of different possible ...
15
votes
2answers
535 views

Could a copper RF cavity like this be reasonably expected to have a Q > 7000?

The paper Measurement of Impulsive Thrust from a Closed Radio-Frequency Cavity in Vacuum (H. White et al, J. Propulsion & Power, November, 2016, http://dx.doi.org/10.2514/1.B36120) refers to an ...
12
votes
6answers
2k views

Why are crystal oscillators used in clocks instead of RLC circuits?

The timing of quartz clocks is regulated by a crystal oscillator. This crystal oscillator effectively forms an RLC circuit. If this is so, what properties does a crystal oscillator have that makes ...
9
votes
4answers
8k views

How to overcome transistor heat in slayer exciter?

I build this circuit and it works but I have two problems. The major problem is that the transistor becomes very hot quickly. I burnt my transistor due to excessive heat. How can I get rid of the very ...
8
votes
2answers
201 views

Need help solving a problem with ac resonance circuits from my uni book

simulate this circuit – Schematic created using CircuitLab Okay I have struggling with this problem for some time and I cant figure out how to solve it. The circuit is in resonance! I tried ...
7
votes
3answers
1k views

Does a voice coil vibrate at the same frequency as the source sound file?

As a disclaimer I know very little about this so I'm probably describing this in a very imprecise way. Say you generated a sine wave on your computer at 800Hz and played it through a speaker. Would ...
7
votes
4answers
563 views

Why does my rectangle function on a FPGA look like this?

I programmed my FPGA to create a simple 1 MHz rectangle function. But when I display the resulting function on my oscilloscope it shows some oscillation after the edges. At first I thought this might ...
5
votes
5answers
2k views

Measure temperature on a moving engine valve: transfer voltage and reading wireless?

I am an automotive engineer with very very little or almost zero electrical/electronics experience. I am working on logging real time temperature values on an engine exhaust valve and mounting a ...
5
votes
4answers
826 views

Is there a clever way to use a small variable capacitor where a larger capacitance is required?

I am designing an activity where students should band pass a song to find a hidden message at 1000Hz. Problem I have considered using a notch filter and tank circuit, but using the formula $$f=\...
5
votes
7answers
8k views

Resonance frequency

How does one find the resonance frequency in a circuit? Wikipedia and the like give some definitions that are not very useful in practice. I found somewhere(I think on this site but I cannot find it ...
5
votes
2answers
553 views

Why use an external resonator with an ATmega microcontroller if it has one built in? [duplicate]

Why should I use an external resonator with an ATmega microcontroller if it has one built in? I'm specifically referring to many of the 8 MHz Arduino boards. A lot, if not most, have an external ...
5
votes
4answers
3k views

Antiresonance of multiple parallel decoupling capacitors: use same value or multiple values?

My quesiton: Is it better practice to put same-valued capacitors in parallel of capacitors of different values to decouple the high-frequency noise caused by digital ICs? Background Digital IC need ...
5
votes
2answers
1k views

What is causing this voltage overshoot?

this is a series resonant half bridge, used with a loosely coupled coils (so there is significant leakage inductance) a decoupling capacitor for the half bridge is used (not shown in schema) (maybe it'...
5
votes
1answer
532 views

Understand simple FM transmitter, inductance, resonance

I learn electronic , I try to understand this project, simplest FM transmitter : The project is describe here : https://makezine.com/projects/super-simple-fm-transmitter/ The inductance of L1 (Strip ...
4
votes
2answers
2k views

LC Circuit problem!

Initially when the switch is closed ,at that instant the inductor is a short and capacitor is open ,so the diode cathode is floating ,so how does the diode conduct? Does the LC circuit resonate? My ...
4
votes
2answers
428 views

Resonant Solenoid Drivers

Over the years I have always wondered why we do not make more use of resonance when driving things like solenoids and relays. We all use the circuit below ad-infinitum and just tolerate the current ...
4
votes
3answers
127 views

Choice of capacitor for high frequency application

I want to recreate this wireless power transfer system that utilizes two resonating LC circuits and induction for power transfer. I want to know the best type of capacitor to use in the LC resonator ...
4
votes
4answers
144 views

What are the drawbacks of transmitting RF frequencies through an antenna that is designed for different frequency?

I've heard of a magic "resonant frequency" that antennas are designed for, what happens if you transmit a frequency through an antenna that does not have the same resonant frequency?
4
votes
1answer
142 views

Connectors that protect wires from breaking when it is resonating alot

I am building a robot vehicle, that is resonating alot when it is in rough areas. Cause of this the wires in the robot will resonate a bit too. When this happens every now and then a 'vein' (tiny ...
4
votes
2answers
991 views

Measuring the resonance point of a piezo ultrasonic transducer

I assume it will be something along the lines of feeding it a sine wave via a resistor and measuring the signal across the resistor as the frequency changes. Does this sound viable? Also, on resonance ...
4
votes
1answer
322 views

Benefits of class E resonant rectifier

I have recently been reading about VHF switch mode power supplies and one thing that I haven't been able to figure out is what really is the point of resonant rectification. I could understand the ...
3
votes
3answers
794 views

What is the wrong with this simple sine wave generator circuit?

I've designed this circuit myself aiming to generate sine wave at the collector of the transistor, but I doesn't work. the current at the collector is DC. Is it a simulator error or the design is ...
3
votes
3answers
2k views

how does current go to infinity in an ideal LC circuit at resonance?

Consider an ideal LC series circuit, excited by a sinusoidal source at resonant frequency. Assume zero initial conditions, for capacitor voltage and inductor current. simulate this circuit – ...
3
votes
3answers
842 views

Intuition for resonant, natural, and oscillatory frequencies of RLC circuits?

I can't seem to get these concepts straight. To start, what are the official definitions of each? My current understanding is that: \$ w_0 = \sqrt{\frac{1}{LC}} \$ is the natural (and resonant?) ...
3
votes
2answers
149 views

Is it absolutely necessary to correct for a temperature drift in the resonant frequency of an ultrasonic transducer?

I'm designing a device which will use ultrasonic transducers in a way similar to sonars. Is it absolutely necessary to correct for the drift in the resonant frequency due to temperature fluctuations? ...
3
votes
1answer
279 views

A question about resonance and crystal radio?

This is a circuit of crystal radio transmitter. I've tested it, and it works properly. but I can't understand everything in this circuit... L1 and C5 make resonance frequency, Would you tell me if ...
3
votes
2answers
168 views

Frequency dependent resistor in real inductor (air coil)?

I tried to measure the resonance frequency of some multi layer air coils. Typical parameters are 0.6 mm copper wire, 3 to 8 layers, and diameter and height are approx 50 mm. I solder a 1 Ohm resistor ...
3
votes
1answer
107 views

Problem with load switching at capacitor resonant frequency

I was watching this video (EEVblog #1117 - PCB Power Plane Capacitance) where the author analyses the impedance curve of the capacitance formed between a PCB's power planes. The comparison with a ...
3
votes
2answers
378 views

What is trimmable “peaking”?

I'm studying Jim Williams application note AN-104 - Load Transient Response Testing for Voltage Regulators, in which he describes an FET-based load transient generator, what might commonly be called ...
3
votes
2answers
128 views

What would be the consequence of the inductor saturating?

The following is a section from a book where it is talking about decoupling by LRC at supply terminals. I highlighted the sentence where I didnt understand: I read that if an inductor has an iron ...
3
votes
1answer
99 views

How to drive a magnet with a coil from an amplifier (to test acoustic guitar resonant frequencies)?

I wish to attach a rare earth magnet to pieces of wood and to acoustic guitars and drive the magnet with a signal generator through an amplifier to a coil. In essence, turning the wood into a ...
3
votes
1answer
104 views

A few questions about AC Circuits

Part A - Series RLC Circuit 1st. Get a Q-factor from the measured voltages at resonance; I know the general formula for Q=1/R*sqrt(L/C) L is 4.7 mH and C is 0.01 microF. R is 100 ohm. If I get Q from ...
2
votes
1answer
1k views

Why do real LC oscillating circuits not oscillate at the resonance frequency?

Consider these two simple LC oscillators with ideal op-amps: simulate this circuit – Schematic created using CircuitLab The resonance frequency is for both circuits about 159 kHz, however ...
2
votes
1answer
1k views

Is electrical impedance at its maximum or minimum, at the acoustic resonant frequency of the material?

For example, if piezo disc has lowest resonant frequency of 4kHz. At that frequency, would the electrical impedance be at its maximum or minimum?
2
votes
1answer
336 views

why do resonant inductive coupling circuit operate at high frequencies?

Just as the title says. Whenever I read a research paper on wireless power transfer via resonant inductive coupling the authors just mention frequencies that range in the kHz and Mhz range, but none ...
2
votes
2answers
845 views

Bandpass vs. Resonance

To pass a certain frequency, you can either have a resonant LC or a bandpass filter made from 2 capacitors and 2 resistors (a high pass and low pass filter put back to back. What is the difference ...
2
votes
1answer
6k views

How to calculate Resonance Frequency of Audio Speaker?

Okay so I searched all over the Web for the resonance frequency of my car speaker so I can properly apply crossover filters, but didn't found any reference of the resonance frequency of this speaker ...
2
votes
3answers
6k views

Why does antenna length have to be at wavelength

Resonance occurs when capacitive and inductive reactances overcome each other. Thus is the familiar resonance frequency equation: As the frequency gets lower, the antenna gets longer. But if this is ...
2
votes
3answers
330 views

Self-resonance frequency of MLCC in Buck converter circuit

Let´s assume I use a synchronous buck converter switching at 1MHz and a 47µF MLCC at its output whose self-resonance frequency is right at 1MHz. For my understanding, using an DC/DC converter output ...
2
votes
2answers
2k views

How can this Parallel LC circuit act as a filter?

How can the network that is shown in the image in any way alter the voltage being supplied to the output? i.e no matter what the response of the LC system, the input voltage is directly transferred to ...
2
votes
1answer
683 views

Can resonance increase frequency?

I would like to know what would happen if a capacitive load is connected to the secondary of a transformer. I simulated the circuit on Proteus. The inductance of the secondary coil was 0.1 H and the ...
2
votes
1answer
1k views

Finding Q for filters

Given the transfer function for a given filter, how can I find a value for the q-factor? For example, I have this transfer function for a Sallen-Key lowpass filter \$ H(s) = \dfrac{1}{R_1R_2C_1C_2s^...
2
votes
2answers
3k views

Understanding a simple crystal oscillator transmitter circuit

I've recently built this circuit: http://makerf.com/posts/mighty_simple_shortwave_transmitter It works on the desired frequency as you can see from this video : https://www.youtube.com/watch?v=...
2
votes
2answers
1k views

Why does the tank circuit of Coplitts oscillator produce 180 phase shift?

http://www.circuitstoday.com/colpitts-oscillator I would like to understand how Coplitts oscillator works. This link says that the tank circuit of Coplitts oscillator produces 180 degrees phase shift....
2
votes
3answers
1k views

Infinite impedance at resonance in parallel LC circuit ? does that mean it is not usable?

In a parallel (tank) LC circuit, this means infinite impedance at resonance. In a series LC circuit, it means zero impedance at resonance: What does that mean? Does this infinite impedance at ...
2
votes
2answers
662 views

How can I obtain the transfer function of an unknown circuit from its bode plot?

I have the following bode plot of some unknown circuit: (The lines denote the -3dB frequencies, f_low and f_high.) I'm guessing it's a high-pass resonant filter. I don't have phase information, other ...
2
votes
1answer
2k views

Cut Off Frequency in three phase LC filter

Good afternoon all My question is what will be the formula to calculate cut off frequency of attached LC filter. Its a three phase LC filter. \$(L1=L2=L3= 6.1 \mathrm{mH}) \;\mathrm{and} \;(C1=...
2
votes
1answer
58 views

Can an electric resonator (like a microwave) be used to effectively heat things other than water at different frequencies?

For example, could you determine the resonant frequency of slag in an ore sample and melt it by putting it in an electric resonator at the appropriate frequency?
2
votes
1answer
38 views

How is Q for surface acoustic wave devices measured?

I do not have a good understanding of Q, the quality factor. I get the basic concept that it has to do with energy losses within a system, particularly oscillating systems like resonators. Higher Q ...
2
votes
1answer
395 views

Isolated Gate Driver Consistent Failure

I have a Tesla coil driver, designed around a UCC21520 isolated gate driver. It is operating as a fixed 50% duty cycle half bridge switcher. The frequency is varied from 150kHz to 250kHz. It is ...