RLC Circuit Calculator

RLC Circuit Calculator

Analyze the resonance and damping characteristics of a series RLC circuit.

Last updated: March 2026 | By ForgeCalc Engineering

Resonant Frequency (f₀)
159.15 Hz
Damping Ratio (ζ)
5.0000
Overdamped

What is an RLC Circuit?

An RLC circuit is an electrical circuit consisting of a resistor (R), an inductor (L), and a capacitor (C), connected in series or in parallel. It is a second-order linear circuit that can oscillate at a specific frequency.

The damping ratio (ζ) determines how the circuit's response decays over time. An underdamped circuit will oscillate before settling, while an overdamped circuit will return to equilibrium without oscillating. Critical damping is the fastest possible return to equilibrium without oscillation.

The Formula

f₀ = 1 / (2π√(LC))
ζ = (R/2)√(C/L)

Where:
f₀ is the resonant frequency (Hz)
ζ (zeta) is the damping ratio
R is resistance (Ω)
L is inductance (H)
C is capacitance (F)

Frequently Asked Questions

What is resonance?

Resonance occurs when the inductive and capacitive reactances cancel each other out, resulting in a purely resistive impedance and maximum current in a series circuit.

Why is critical damping important?

Critical damping is ideal for systems like car suspensions or analog meter needles, where you want the fastest possible response without any 'overshoot' or oscillation.

How does resistance affect resonance?

Resistance doesn't change the resonant frequency itself, but it determines the 'sharpness' or Q-factor of the resonance peak and the damping of the system.

What is the Q-factor?

The Quality (Q) factor is the ratio of the resonant frequency to the bandwidth. A high Q means a sharp, narrow resonance with low energy loss.

Related Tools