Resonanssipiiristöä

Resonanssipiiristöä, or resonant circuit, is an electrical circuit composed of an inductor and a capacitor. This combination exhibits resonant behavior, meaning it can store and transfer electrical energy between the inductor's magnetic field and the capacitor's electric field at a specific frequency. This characteristic frequency is known as the resonant frequency.

At resonance, the impedance of a series resonant circuit becomes purely resistive and reaches its minimum value. Conversely, the impedance of a parallel resonant circuit becomes purely resistive and reaches its maximum value. This frequency-dependent behavior makes resonant circuits extremely useful in various electronic applications.

The primary function of a resonant circuit is to select or reject specific frequencies. This is achieved by tuning the circuit, typically by adjusting the capacitance or inductance, to match the desired frequency. When the input signal's frequency matches the resonant frequency, the circuit allows maximum current or voltage to pass through (depending on the configuration), while significantly attenuating signals at other frequencies.

Common applications of resonant circuits include tuning in radio receivers and transmitters, filtering unwanted frequencies in signal processing, and in oscillators to generate specific frequencies. The quality factor (Q factor) is a parameter that describes how sharp the resonance is, indicating the circuit's ability to discriminate between frequencies. A higher Q factor means a narrower bandwidth and a more selective circuit.