An LC tank circuit (also called a resonant circuit) is one of the most important building blocks in electronics. Use this calculator to quickly solve for resonant frequency, inductance, or capacitance using the standard resonance equation.
LC Tank Resonance Calculator
Enter inductance and capacitance to calculate resonant frequency.
Formula: f0 = 1 / (2π√(LC))
What Is an LC Tank Circuit?
An LC tank is a circuit made from an inductor (L) and a capacitor (C). Energy oscillates back and forth between the magnetic field of the inductor and the electric field of the capacitor. At one specific frequency, called the resonant frequency, this exchange is most efficient.
LC resonators appear in RF filters, oscillators, antenna matching networks, radio tuners, and timing circuits. If you have worked with resonance, impedance peaks, or narrow-band filtering, you have already touched LC tank behavior.
The Core Equation
For an ideal LC tank, resonant frequency is:
f = 1 / (2π√(LC))
- f = resonant frequency (Hz)
- L = inductance (H)
- C = capacitance (F)
If you know any two variables, you can solve for the third. That is exactly what the calculator above does.
How to Use This LC Tank Calculator
1) Choose your target variable
Use the Solve for dropdown to choose whether you want frequency, inductance, or capacitance.
2) Enter known values with units
You can enter values in practical engineering units such as µH, nF, kHz, MHz, and GHz.
3) Click Calculate
The tool returns the requested value plus extra details like angular frequency and oscillation period when frequency is computed.
Worked Example
Suppose you have:
- L = 10 µH
- C = 100 nF
Then resonance is approximately 159.15 kHz. This gives you a quick starting point for a tuned stage in a communication or sensing design.
Practical Design Notes
Real components are not ideal
Actual inductors and capacitors include losses, parasitic resistance, and parasitic capacitance/inductance. These effects shift resonance and reduce Q-factor.
Tolerance matters
If your inductor is ±10% and capacitor is ±5%, resonant frequency can move significantly. For narrow-band circuits, use tighter tolerances or add tuning elements.
Watch self-resonance and ESR
At high frequencies, an inductor may approach self-resonance and stop behaving as a clean inductor. Capacitor ESR and ESL can also impact performance.
Common Use Cases
- RF oscillator design
- Band-pass and notch filter tuning
- Antenna matching and front-end selectivity
- Inductive sensing and wireless power experiments
- Educational resonance demonstrations
Quick FAQ
Does series vs. parallel LC change the resonance formula?
For ideal components, both use the same resonance frequency equation. However, impedance behavior around resonance differs between series and parallel forms.
Can I use this for high-frequency RF design?
Yes, as a first-order estimate. For precision RF work, include parasitics, PCB layout, device models, and simulation (SPICE or RF tools).
What if I get an unrealistic value?
Check units first. A mismatch between nF and pF, or kHz and MHz, is the most common source of major calculation errors.
Final Thoughts
This LC tank calculator is designed for fast engineering estimates with clear unit handling. Use it to speed up your resonance calculations, then refine with measured component data and simulation for production-grade results.