LC Resonant Frequency & Tank Circuit Calculator
LC tank circuits form the core of RF radio transmitters, receivers, oscillators, bandpass filters, and wireless power coils.
How it works
At resonance, energy oscillates back and forth between the magnetic field of the inductor and the electric field of the capacitor with zero net reactive impedance.
Formula
f_0 = (1 / 2π √(LC)), ω_0 = (1 / √(LC))
Calculates the exact frequency where inductive reactance (X_L = 2πfL) cancels capacitive reactance (X_C = 1/(2πfC)).
| Symbol | Variable | Unit | Description |
|---|---|---|---|
| L | Inductance | H | |
| C | Capacitance | F | |
| f_0 | Natural resonant frequency | Hz | |
| ω_0 | Angular resonance frequency | rad/s |
Worked example
1 mH Inductor with 100 nF Capacitor
- Inductance:
- 0.001 H (1 mH)
- Capacitance:
- 0.0000001 F (100 nF)
f₀ = 1 / (2π × √(0.001 × 1e-7)) = 15,915.49 Hz (15.915 kHz). Angular velocity ω₀ = 100,000 rad/s.
Limitations
Does not calculate damping attenuation from series winding resistance (DCR) or dielectric leakage.
Frequently asked questions
What is an LC tank circuit?
An LC circuit connects an inductor and capacitor in parallel or series. It acts as an electrical resonator capable of storing and filtering oscillating electric energy at its resonant frequency.
How does resonance affect circuit impedance?
In a series LC circuit, impedance reaches a minimum (ideally 0Ω) at resonance. In a parallel LC circuit, impedance reaches a maximum (ideally infinite), blocking or trapping signals at f₀.
What is Q factor in resonant circuits?
The Quality Factor (Q) measures circuit damping and frequency selectivity. High Q circuits produce narrower, sharper resonance peaks with lower energy loss.
Related calculators
Ohm's Law & Electric Power Calculator
Calculate Voltage (V), Current (I), Resistance (R), and Electric Power (P) in electrical circuits using Ohm's Law and Joule's Law.
Resistive Voltage Divider Calculator
Calculate the output voltage (V_out) and current of a two-resistor voltage divider network for microcontroller ADC level shifting and sensor interfacing.
Online Scientific Calculator
Free advanced online scientific calculator with full trigonometric, logarithmic, exponential, root, factorial, and hyperbolic functions.
Torque & Moment of Force Calculator
Calculate rotational torque (τ), moment of force, and foot-pounds from lever arm radius, applied force, and angle.
Last reviewed: 2026-08-22.