RLC Resonance
The current in a driven series RLC circuit against frequency, or equally the voltage across its resistor: a peak at the resonant frequency f₀ whose sharpness is set by the quality factor Q. Use it for AC resonance labs and other resonances measured as a current or a velocity.
Fit the example dataStart with your own data
Example: simulated resistor voltage in a series RLC circuit (10 mH, 1 µF, 33 Ω), 30 points with y uncertainties, opened as a new copy you can edit.
Parameters
- Peak height above the baseline, reached at x = f₀.
- Resonant frequency, in the units of x: 1/(2π√(LC)) in hertz, or 1/√(LC) as an angular frequency. Reported as positive.
- Quality factor: f₀ divided by the full width of the peak at 1/√2 of its height. For a series circuit, Q = √(L/C)/R. Reported as positive.
- Constant baseline, for an offset in the measurement. Enter 0 as its Guess and check Fix if there is none.
Tips
- x must be positive. Enter the driving frequency in hertz or as an angular frequency; f₀ is reported in the same units.
- The peak lies exactly at f₀ and falls to 1/√2 of its height at points f₀/Q apart, so f₀/Q is the half-power bandwidth.
- For the capacitor’s voltage, or a mechanical oscillator’s displacement, use Driven Oscillator Amplitude, whose peak lies a little below the natural frequency.
- Sweep well past the peak on both sides, with closer points near f₀. On a logarithmic x axis the curve is symmetric about f₀.