Electromagnetism
Linked steady-state RLC
This analytic steady-state bench shows phasor Z, I, and phase for the same R, L, C; the separate Circuits preset models its switch transient.
Same RLC in Circuits — interactive physics simulation. This analytic steady-state bench shows phasor Z, I, and phase for the same R, L, C; the separate Circuits preset models its switch transient.
RLC transients
Steady-state phasor RLC; Circuits shows the switching transient.
This analytic steady-state bench shows phasor Z, I, and phase for the same R, L, C; the separate Circuits preset models its switch transient.
- ω₀ = 1/√(LC)
- Link to Circuits lab
Investigation brief
Plan the question before you open the lab
The brief mirrors the prerendered page: driving question, competing predictions, variable roles, governing laws, setup, analysis and extension prompts remain visible and in this order.
Driving question
This experiment uses the exact same R, L, C values as the rlc-series circuits experiment, viewed here as a phasor/AC problem instead of a switch-on transient. As you sweep the drive frequency away from resonance in either direction, does the current amplitude always decrease?
Predictions to weigh
- Yes — moving away from resonance in either direction (higher or lower ω) decreases the current amplitude, since impedance rises on both sides.
- Current amplitude only decreases for frequencies above resonance.
- Current amplitude only decreases for frequencies below resonance.
Variable roles
What you set:
- Drive frequency ω (rad/s)
What you measure:
- Peak current amplitude I_peak (A)
How the investigation runs
- Open the rlc-in-circuits preset and press Reset. R = 20 Ω, L = 1 H, C = 0.01 F, V₀ = 10 V — identical to the rlc-series circuits experiment's components.
- Enable the current-amplitude readout.
- Set the drive angular frequency for each trial (as a multiple of ω₀ = 10 rad/s) and record the peak current amplitude.
What the printable worksheet asks students to work out
- For one trial, compute Z = √(R² + (ωL − 1/(ωC))²) using R = 20 Ω, L = 1 H, C = 0.01 F, then I_peak = V₀/Z using V₀ = 10 V. Compare to the table.
- Confirm your two off-resonance trials (below and above ω₀) give equal current amplitude when equally spaced from resonance in this specific case. Explain why current amplitude peaks exactly at ω₀ and falls off symmetrically on a log-frequency scale.
Where this shows up beyond the lab
- The rlc-series circuits experiment shows this same hardware's step response (switch-on transient) to a constant 10 V battery, not a sinusoidal drive. Explain why 'impedance' and 'resonance' are AC-steady-state concepts that don't directly apply to that DC switch-on scenario.
- How sharply current amplitude drops off away from resonance is described by a circuit's 'quality factor' Q = ω₀L/R. Using this circuit's R = 20 Ω, L = 1 H, ω₀ = 10 rad/s, compute Q and explain whether this circuit has a sharp or broad resonance peak.
- AP Physics 2 — Unit 12: Magnetism and Electromagnetism
- AP Physics C: Electricity and Magnetism — Unit 13: Electromagnetic Induction
- IB Physics — D.4 Induction
- General High School Physics — Magnetism & electromagnetism
- NGSS High School Physics — Electric current and magnetic fields
- Welcome to Rlc In Circuits
- Select the RLC circuit
- Press Play
- Same physics in Circuits
- Open the Properties panel
- You did it!
Open the interactive simulation to build the scene, press Play, and explore with live measurements and a guided tutorial.