Driven RLC Circuit (LC Resonance)
Drive a series RLC circuit with an AC source — sweep the drive frequency through the resonant frequency and watch the steady-state current amplitude peak, with the peak's sharpness controlled by the circuit's resistance.
Preview — sign up free to change the numbers yourself
What you can adjust
- Inductance (L)
- 0.01 – 1 H
- Capacitance (C)
- 0.000001 – 0.0001 F
- Resistance (R)
- 1 – 200 ohm
- Drive frequency (f_d)
- 1 – 3000 Hz
- Drive voltage amplitude (V0)
- 1 – 20 V
Bigger inductance lowers the resonant frequency f0 = 1/(2*pi*sqrt(L*C)).
Real capacitors in this range are usually specified in microfarads (1e-6 F = 1uF). Bigger capacitance also lowers f0.
Must be above 0 so the resonance peak always stays finite. Small resistance gives a tall, sharp peak (high Q); large resistance gives a low, broad one.
Sweep this through the resonant frequency f0 to watch the steady-state current amplitude climb to its peak (I0 = V0/R exactly at resonance), then fall back off on either side.
The AC source's peak voltage — scales the current amplitude at every frequency, never shifts where the peak sits.
About this simulation
What it shows
A coil, a capacitor and a resistor in series are driven by an AC source. The current rings briefly and then settles, and a resonance curve shows where your drive frequency sits against the circuit's peak.
The key idea
The circuit responds most strongly at f₀ = 1/(2π√(LC)), where the current reaches V₀/R. A small resistance gives a tall, narrow peak and a large one gives a low, broad peak.
Try this
With Drive frequency (f_d) at 159 Hz, raise Resistance (R) from 10 to 50 ohm: the peak current drops from about 0.5 A to 0.1 A.