Resonaattori

Resonaattori, or resonator in English, denotes a device or structure that stores energy in a particular mode of oscillation and responds most strongly at specific frequencies. When driven near its natural frequency, it exhibits amplified oscillations and a characteristic resonance peak; away from resonance, the response diminishes. The behavior is described by a resonance curve and quantified by parameters such as the natural frequency and the quality factor, or Q, which measures the sharpness of the peak and the energy losses.

Resonators occur in many physical domains. Mechanical resonators include tuning forks, pendulums, membranes and cantilevers. Electrical resonators use reactive components such as inductors and capacitors, with quartz crystal resonators providing stable timing references. Acoustic resonators involve air columns or cavities in instruments and resonators in percussion. Optical resonators use mirrors or waveguides to trap light, as in laser cavities. In the microwave and RF range, cavities and resonators support standing waves at chosen frequencies.

Applications include frequency selection and filtering in communication systems, timing in clocks and oscillators, sensors that detect changes in mass, force, or temperature through shifts in resonance, and laser technology. Resonators are often deliberately coupled to drivers or detectors to create selective response, and their performance depends on losses, coupling strength, and mechanical or material properties.

Origin of the term lies in Latin resonare, to resound; Finnish usage mirrors the same concept across physics, engineering and acoustics. See also resonance, Q factor, damping.