# Resonance

resonantresonant frequencyresonance frequencyresonateresonant frequenciesresonancesresonance frequenciesresonatingresonant vibrationresonates
In mechanical systems, resonance is a phenomenon that occurs when the frequency at which a force is periodically applied is equal or nearly equal to one of the natural frequencies of the system on which it acts.wikipedia
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### Electrical resonance

resonanceresonateResonant
For example, electrical resonance occurs in a circuit with capacitors and inductors because the collapsing magnetic field of the inductor generates an electric current in its windings that charges the capacitor, and then the discharging capacitor provides an electric current that builds the magnetic field in the inductor. Electrical resonance of tuned circuits in radios and TVs that allow radio frequencies to be selectively received
Electrical resonance occurs in an electric circuit at a particular resonant frequency when the impedances or admittances of circuit elements cancel each other.

### Self-oscillation

Some behavior is mistaken for resonance but instead is a form of self-oscillation, such as aeroelastic flutter, speed wobble, or Hunting oscillation.
Self-oscillators are therefore distinct from forced and parametric resonators, in which the power that sustains the motion must be modulated externally.

### Acoustic resonance

resonanceresonatorresonant
Resonance phenomena occur with all types of vibrations or waves: there is mechanical resonance, acoustic resonance, electromagnetic resonance, nuclear magnetic resonance (NMR), electron spin resonance (ESR) and resonance of quantum wave functions.
Acoustic resonance is a phenomenon where acoustic systems amplify sound waves whose frequency matches one of its own natural frequencies of vibration (its resonance frequencies).

### Nuclear magnetic resonance

NMRmagnetic resonancenuclear magnetic resonance (NMR)
Resonance phenomena occur with all types of vibrations or waves: there is mechanical resonance, acoustic resonance, electromagnetic resonance, nuclear magnetic resonance (NMR), electron spin resonance (ESR) and resonance of quantum wave functions.
This process occurs near resonance, when the oscillation frequency matches the intrinsic frequency of the nuclei, which depends on the strength of the static magnetic field, the chemical environment, and the magnetic properties of the isotope involved; in practical applications with static magnetic fields up to ca. 20 tesla, the frequency is similar to VHF and UHF television broadcasts (60–1000 MHz).

### Standing wave

standing wavesstationary wavestationary waves
This produces standing waves, and only certain patterns and frequencies of radiation are sustained, due to the effects of interference, while the others are suppressed by destructive interference.
The most common cause of standing waves is the phenomenon of resonance, in which standing waves occur inside a resonator due to interference between waves reflected back and forth at the resonator's resonant frequency.

### Natural frequency

natural frequencieseigen-frequencyeigenfrequency
In mechanical systems, resonance is a phenomenon that occurs when the frequency at which a force is periodically applied is equal or nearly equal to one of the natural frequencies of the system on which it acts.
If the oscillating system is driven by an external force at the frequency at which the amplitude of its motion is greatest (close to a natural frequency of the system), this frequency is called resonant frequency.

### LC circuit

tuned circuitLCresonant circuit
Electrical resonance of tuned circuits in radios and TVs that allow radio frequencies to be selectively received
The circuit can act as an electrical resonator, an electrical analogue of a tuning fork, storing energy oscillating at the circuit's resonant frequency.

### Balance wheel

foliotcompensation balanceauxiliary temperature compensation
Timekeeping mechanisms of modern clocks and watches, e.g., the balance wheel in a mechanical watch and the quartz crystal in a quartz watch Clocks keep time by mechanical resonance in a balance wheel, pendulum, or quartz crystal.
The balance wheel and hairspring together form a harmonic oscillator, which due to resonance oscillates preferentially at a certain rate, its resonant frequency or 'beat', and resists oscillating at other rates.

### Tidal resonance

Tidal resonance of the Bay of Fundy
In oceanography, a tidal resonance occurs when the tide excites one of the resonant modes of the ocean.

### Inductor

inductorscoilinductive
For example, electrical resonance occurs in a circuit with capacitors and inductors because the collapsing magnetic field of the inductor generates an electric current in its windings that charges the capacitor, and then the discharging capacitor provides an electric current that builds the magnetic field in the inductor.
This capacitive reactance rises with frequency; at some frequency, the inductor will behave as a resonant circuit, becoming self-resonant.

### Vibration

vibrationsvibratevibrating
Friction idiophones, such as making a glass object (glass, bottle, vase) vibrate by rubbing around its rim with a fingertip
The mechanical system vibrates at one or more of its natural frequencies and damps down to motionlessness.

### Optical cavity

optical resonatorcavitylaser cavity
In optical cavities, light confined in the cavity reflects back and forth multiple times.
Light confined in the cavity reflects multiple times producing standing waves for certain resonance frequencies.

Electrical resonance of tuned circuits in radios and TVs that allow radio frequencies to be selectively received
The transmitter sends the modulated electrical energy to a tuned resonant antenna; this structure converts the rapidly changing alternating current into an electromagnetic wave that can move through free space (sometimes with a particular polarization).

### Pendulum

pendulumssimple pendulumpendula
This is analogous to a mechanical pendulum, where mechanical energy is converted back and forth between kinetic and potential, and both systems are forms of simple harmonic oscillators. Clocks keep time by mechanical resonance in a balance wheel, pendulum, or quartz crystal.
The reason harmonic oscillators are used in clocks is that they vibrate or oscillate at a specific resonant frequency or period and resist oscillating at other rates.

### Watch

wristwatchwatchesdigital watch
Timekeeping mechanisms of modern clocks and watches, e.g., the balance wheel in a mechanical watch and the quartz crystal in a quartz watch
It resonates at a specific highly stable frequency, which is used to accurately pace a timekeeping mechanism.

### Capacitor

capacitorscapacitivecondenser
For example, electrical resonance occurs in a circuit with capacitors and inductors because the collapsing magnetic field of the inductor generates an electric current in its windings that charges the capacitor, and then the discharging capacitor provides an electric current that builds the magnetic field in the inductor.
Using this measurement method, the dielectric constant may exhibit a resonance at certain frequencies corresponding to characteristic response frequencies (excitation energies) of contributors to the dielectric constant.

### Spectroscopy

spectroscopiclaser spectroscopyspectroscopist
Material resonances in atomic scale are the basis of several spectroscopic techniques that are used in condensed matter physics
One of the central concepts in spectroscopy is a resonance and its corresponding resonant frequency.

### Speed wobble

shimmyTank-slapperanti-shimmy
Some behavior is mistaken for resonance but instead is a form of self-oscillation, such as aeroelastic flutter, speed wobble, or Hunting oscillation.
As the wheel rotates, it will exert a cyclic load to the vehicle frame, which if matched with the system's (vehicle and attached accessories) resonant frequency, can produce a speed wobble.

### Q factor

quality factorQQ'' factor
Optical cavities are designed to have a very large Q factor.
Q factor is a parameter that describes the resonance behavior of an underdamped harmonic oscillator (resonator).

### Tuned mass damper

mass damperdampertuned mass dampers
The Taipei 101 building relies on a 660 t—a tuned mass damper—to cancel resonance.
Typically, the dampers are huge concrete blocks or steel bodies mounted in skyscrapers or other structures, and moved in opposition to the resonance frequency oscillations of the structure by means of springs, fluid or pendulums.

### Electron paramagnetic resonance

electron spin resonanceEPRESR
Resonance phenomena occur with all types of vibrations or waves: there is mechanical resonance, acoustic resonance, electromagnetic resonance, nuclear magnetic resonance (NMR), electron spin resonance (ESR) and resonance of quantum wave functions.
The halfwidth \Delta B_h is the distance measured from the line's center to the point in which absorption value has half of maximal absorption value in the center of resonance line.

### Optical ring resonators

ring resonatorsring resonatormicroring resonators
Ring resonators and whispering galleries are examples of optical resonators that do not form standing waves.
When light of the resonant wavelength is passed through the loop from input waveguide, it builds up in intensity over multiple round-trips due to constructive interference and is output to the output bus waveguide which serves as a detector waveguide.

### Flute

flautistflutistflutes
Acoustic resonance is an important consideration for instrument builders, as most acoustic instruments use resonators, such as the strings and body of a violin, the length of tube in a flute, and the shape of, and tension on, a drum membrane.
The flutist changes the pitch of the sound produced by opening and closing holes in the body of the instrument, thus changing the effective length of the resonator and its corresponding resonant frequency.

### Clock

clockstimepiecemechanical clock
Clocks keep time by mechanical resonance in a balance wheel, pendulum, or quartz crystal.
The advantage of a harmonic oscillator over other forms of oscillator is that it employs resonance to vibrate at a precise natural resonant frequency or 'beat' dependent only on its physical characteristics, and resists vibrating at other rates.

### Magnetic resonance imaging

MRImagnetic resonance imaging (MRI)magnetic resonance
NMR is also routinely used in advanced medical imaging techniques, such as in magnetic resonance imaging (MRI).
First, energy from an oscillating magnetic field temporarily is applied to the patient at the appropriate resonance frequency.