Calculadora de Frecuencia Resonante

Ingresa inductancia y capacitancia para calcular la frecuencia resonante del circuito. Incluye factor Q, ancho de banda, impedancia y curva de respuesta SVG interactiva.

Input Values

Resistance (R)

Inductance (L)

Capacitance (C)

Series RLC Result

fr = 1 / (2π√(LC))

50.33 kHz

Q Factor

0.32

Bandwidth (BW)

159.2 kHz

Z @ fr

100.00 Ω

XL = XC

31.62 Ω

Test Frequency

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What is Resonant Frequency?

Resonant frequency is the frequency at which an RLC circuit's impedance reaches its minimum (series) or maximum (parallel). At resonance, the inductive reactance (XL) equals the capacitive reactance (XC), and the circuit behaves as a purely resistive load. The resonant frequency is calculated using fr = 1/(2π√LC), where L is inductance and C is capacitance.

How to Use This Calculator

Select the circuit type: Series RLC, Parallel RLC, or LC Tank.
Enter the inductance (L) value and select the unit (µH, mH, or H). Use preset buttons for common values.
Enter the capacitance (C) value and select the unit (pF, nF, or µF).
For Series and Parallel RLC, enter the resistance (R) value.
View the resonant frequency, Q factor, bandwidth, and impedance at resonance.
Enter a test frequency to see impedance, phase, XL, and XC at that specific frequency.
Use the SVG impedance chart to visualize the frequency response.

Frequently Asked Questions

What is the difference between series and parallel RLC resonance?

In a series RLC circuit, impedance is minimum at resonance (Z = R), allowing maximum current flow. In a parallel RLC circuit, impedance is maximum at resonance, blocking current flow. The resonant frequency formula fr = 1/(2π√LC) is the same for both, but the Q factor formulas differ: series Q = (1/R)√(L/C) and parallel Q = R√(C/L).

What does the Q factor mean?

The Q (quality) factor measures the sharpness of the resonance peak. A higher Q means a narrower bandwidth and more selective frequency response. Q is the ratio of resonant frequency to bandwidth: Q = fr/BW. In practical terms, higher Q circuits are better at filtering specific frequencies but have less tolerance for component variations.

What is an LC tank circuit?

An LC tank (or LC resonant circuit) consists of only an inductor and capacitor with no intentional resistance. It oscillates at the resonant frequency fr = 1/(2π√LC), storing energy alternately in the magnetic field of the inductor and the electric field of the capacitor. Real LC tanks always have some parasitic resistance, which causes the oscillations to decay over time.

How is bandwidth related to Q factor?

Bandwidth (BW) is inversely proportional to Q factor: BW = fr/Q. A high-Q circuit has a narrow bandwidth (highly selective), while a low-Q circuit has a wide bandwidth. The bandwidth defines the frequency range between the -3dB points where the power drops to half its peak value.

What happens to impedance at frequencies above and below resonance?

Below resonance, a series RLC circuit is capacitive (XC > XL), and above resonance it's inductive (XL > XC). For a parallel RLC circuit, the behavior is opposite: below resonance it's inductive, and above resonance it's capacitive. At exactly the resonant frequency, the reactive components cancel out.