Resonant Frequency Calculator

Calculate resonant frequency for LC circuits, tank circuits, and tuned circuits with inductance and capacitance

Calculate LC Circuit Resonant Frequency

Inductance of the inductor in the LC circuit

Capacitance of the capacitor in the LC circuit

LC Circuit Analysis Results

0.000 Hz
Resonant Frequency (f₀)
0.000e+0
Angular Frequency (ω) rad/s
0.000 fs
Time Period (T)
0.000 nm
Wavelength (λ)

Formula used: f₀ = 1 / (2π √(LC))

Input values: L = 0.000e+0 H, C = 0.000e+0 F

LC Product: 0.000e+0 H·F

Frequency Range Analysis

Example Calculation

FM Radio Tank Circuit

Application: FM radio tuning circuit at 100 MHz

Inductance (L): 2.53 μH (microhenries)

Capacitance (C): 1.0 pF (picofarads)

Circuit Type: Parallel LC tank circuit for frequency selection

Calculation

f₀ = 1 / (2π √(LC))

f₀ = 1 / (2π √(2.53×10⁻⁶ × 1.0×10⁻¹²))

f₀ = 1 / (2π √(2.53×10⁻¹⁸))

f₀ = 1 / (2π × 1.59×10⁻⁹)

f₀ = 100.0 MHz

LC Circuit Configurations

Series LC Circuit

Inductor and capacitor connected in series. Minimum impedance at resonance.

Used in: Bandpass filters, oscillator feedback

Parallel LC Circuit

Inductor and capacitor connected in parallel. Maximum impedance at resonance.

Used in: Tank circuits, oscillators, frequency selection

Common Applications

📻

Radio Tuning

Selecting specific radio frequencies

🔊

Audio Filters

Crossover networks in speakers

Oscillators

Signal generation circuits

📡

Antenna Matching

Impedance matching networks

Quick Reference

Resonant Frequency:
f₀ = 1 / (2π√(LC))
Angular Frequency:
ω₀ = 2πf₀ = 1/√(LC)
At Resonance:
X_L = X_C
Quality Factor:
Q = √(L/C) / R

Understanding LC Circuit Resonance

What is Resonant Frequency?

The resonant frequency is the natural frequency at which an LC circuit oscillates when energy is transferred back and forth between the magnetic field of the inductor and the electric field of the capacitor. At this frequency, the inductive and capacitive reactances are equal and cancel each other out.

Physical Principles

  • Energy oscillates between electric and magnetic fields
  • Inductive reactance X_L = 2πfL increases with frequency
  • Capacitive reactance X_C = 1/(2πfC) decreases with frequency
  • At resonance: X_L = X_C, total reactance = 0

Formula Derivation

At resonance: X_L = X_C
2πf₀L = 1/(2πf₀C)
(2πf₀)²LC = 1
f₀² = 1/(4π²LC)
f₀ = 1/(2π√(LC))

Key Characteristics

  • Frequency depends only on L and C values
  • Independent of resistance (ideal case)
  • Maximum energy transfer at resonance
  • Forms basis for oscillators and filters

Series LC Circuit

  • • Minimum impedance at resonance (Z = R only)
  • • Maximum current at resonant frequency
  • • Behaves as bandpass filter
  • • Used in tuned amplifiers and filters

Parallel LC Circuit

  • • Maximum impedance at resonance
  • • Minimum current from source at resonance
  • • Acts as tank circuit storing energy
  • • Used in oscillators and frequency selection