LC Tank Circuit Calculator
Use this tool to calculate resonant frequency, inductance, or capacitance for an ideal LC tank circuit.
Formula used: f = 1 / (2π√(LC))
What Is an LC Tank Circuit?
An LC tank circuit is a resonant circuit built from an inductor (L) and capacitor (C). Energy moves back and forth between the magnetic field of the inductor and the electric field of the capacitor. At a specific frequency, called the resonant frequency, this energy exchange is most efficient.
LC tanks are used in RF design, oscillators, tuners, filters, impedance matching networks, and sensor circuits. If you work with radio systems or analog electronics, you will use this equation regularly.
Core Resonance Formula
The ideal resonant frequency for an LC circuit is:
f = 1 / (2π√(LC))
- f = frequency in hertz (Hz)
- L = inductance in henries (H)
- C = capacitance in farads (F)
Rearranging gives:
- L = 1 / ((2πf)2 C)
- C = 1 / ((2πf)2 L)
How to Use This Calculator
1) Choose what you want to solve
Select whether you want resonant frequency, inductance, or capacitance.
2) Enter known values and units
Input your numbers and select appropriate engineering units (µH, nF, MHz, etc.). The calculator converts everything to SI base units internally.
3) Click calculate
The tool displays the computed value and also reports useful related values such as angular frequency and period.
Practical Design Notes
Real parts are not ideal
Real inductors include winding resistance and parasitic capacitance. Real capacitors include ESR, ESL, and tolerance. This means measured resonance may differ from ideal math.
Quality factor (Q) matters
A higher Q means lower loss and a narrower bandwidth around resonance. In RF circuits, Q has major impact on selectivity and phase noise.
Tolerance and temperature drift
- Component tolerance shifts center frequency.
- Temperature coefficients can move resonance over time.
- For precision designs, use tight-tolerance NP0/C0G capacitors and stable core materials.
Typical Applications
- Radio tuning stages
- Crystal replacement oscillators and VCO support networks
- Band-pass and notch filters
- NFC and RFID resonant loops
- Wireless power transfer resonant links
Quick Example
Suppose you have L = 10 µH and C = 100 nF. The resonant frequency is approximately 159.15 kHz. You can verify this by selecting “Resonant Frequency,” entering those values, and clicking calculate.
Final Thoughts
LC resonance is one of the most important building blocks in analog and RF electronics. A fast, unit-aware calculator helps you move from concept to prototype quickly and with fewer mistakes. Use this page for initial design, then validate with simulation and bench measurement for production-level work.