Calculator inputs
Choose the unknown you want to solve, enter the known values, then submit to generate a detailed resonance report.
Formula used
Resonant frequency: f = 1 / (2π√LC)
Angular frequency: ω₀ = 1 / √LC = 2πf
Period: T = 1 / f = 2π√LC
Inductance from target frequency: L = 1 / ((2πf)²C)
Capacitance from target frequency: C = 1 / ((2πf)²L)
Reactance magnitude at resonance: XL = XC = √(L/C)
How to use this calculator
- Select the calculation mode based on the unknown you want to solve.
- Enter the known inductance, capacitance, or frequency values with their correct units.
- Optionally enter peak voltage or peak current to estimate stored energy in the tank.
- Choose precision and the sweep variable for the Plotly response graph.
- Submit the form to view the result table, graph, and export options above the form.
Example data table
These sample LC combinations help you compare how resonant frequency changes as inductance and capacitance vary.
| Example | Inductance | Capacitance | Resonant Frequency | Period |
|---|---|---|---|---|
| 1 | 10 uH | 100 pF | 5.03292 MHz | 198.69177 ns |
| 2 | 47 uH | 220 pF | 1.56516 MHz | 638.91067 ns |
| 3 | 100 uH | 1 nF | 503.29212 kHz | 1.98692 us |
| 4 | 1 mH | 10 nF | 50.32921 kHz | 19.86918 us |
| 5 | 2.2 mH | 47 nF | 15.65164 kHz | 63.89107 us |
Frequently asked questions
1. What does an LC tank do?
An LC tank stores energy by moving it between an inductor's magnetic field and a capacitor's electric field. That exchange creates oscillation at a natural resonant frequency set by L and C.
2. Why does increasing capacitance reduce frequency?
The resonant formula places capacitance inside the square root in the denominator. A larger capacitance increases the denominator, so the oscillation slows and the resonant frequency falls.
3. Why does increasing inductance reduce frequency?
Higher inductance also enlarges the square-root term in the denominator. The tank takes longer to exchange stored energy, so the oscillation period increases and the frequency decreases.
4. Is this calculator valid for real circuits?
It is accurate for ideal design estimates. Real circuits include parasitic resistance, winding capacitance, component tolerance, and layout effects, so measured resonance may shift slightly from the calculated value.
5. What units can I enter?
You can enter common inductance, capacitance, and frequency units such as H, mH, uH, nH, F, uF, nF, pF, Hz, kHz, MHz, and GHz. The calculator converts them internally.
6. What is reactance at resonance?
At resonance, the inductor and capacitor have equal reactance magnitude. Their opposite signs cancel in an ideal tank, enabling the strongest energy exchange at the natural oscillation frequency.
7. Why are peak voltage and current optional?
They are only needed for energy estimates. The core resonance equations need just L and C, or one of them plus a target frequency, to solve the main tank properties.
8. When should I use the graph?
Use the graph when you want quick sensitivity insight. It shows how resonant frequency moves as inductance or capacitance changes, helping you judge tuning range and component tolerance impact.