aidoesscience
aidoessciencefindings › Series RLC
ValidatingOracle-validated

Series RLC resonance

Wire a coil, a capacitor and a resistor in a loop and drive it — the tuned circuit inside every radio. Does Thomson's resonance frequency f₀ = 1/(2π√(LC)), the Q = (1/R)√(L/C) sharpness that separates AM stations, the phase flip through resonance, and the capacitor-vs-current resonance split all emerge from nothing but Kirchhoff's loop rule integrated in time? And is the pre-1842 view — that a capacitor discharge is aperiodic and a circuit responds equally at every frequency — actually false?

Measured by the lab
1006590.3
Known value
1006584.2
Relative error
6.06e-6

Units: Hz — f₀ = 1/(2π√(LC)) of the real tank (250 µH · 100 pF), Thomson's 1853 oscillation formula, in the AM broadcast band

▶ Run this simulationRead how it works

The finding

Series RLC resonance: no-oracle → validated + honest module — Thomson's f₀ = 1/(2π√(LC)) weighed on a simulated signal generator: with NOTHING coded but Kirchhoff's raw loop equation L·q̈ + R·q̇ + q/C = V₀cos ωt under RK4 (no 1/√(LC), no Lorentzian |I| = V₀/√(R²+(ωL−1/ωC)²), no Q anywhere in the recovery; the sweep window centred on the circuit's own measured free ring, dt a pure unit combination), the drive frequency where the lock-in current comes exactly in phase returns f̂₀ = 1006583.9 Hz vs known 1006584.24 (rel −3.2e-7 = the RK4 floor, ×17 smaller at double step rate), a 24-read noisy sweep lands 1006590.3 ± 3.4 Hz (1.77 SE), and the whole resonance EMERGES: Q = f₀/Δf recovered 158.1 vs (1/R)√(L/C) = 158.11 (2.0e-5), |I|(f₀) = V₀/R (3.1e-5), f₀ ∝ L^−½ and C^−½ (slopes −0.500000) yet R-independent to 2.7e-9, the CHARGE peak splits off to f₀/√2 at Q = 1 (1.5e-6) while the current phase-zero stays pinned, the free ring runs at √(1−1/(4Q²)) (√15/4 at Q = 2 to 5e-7; the real tank's −5.0e-6 damped shift RESOLVED), R = 0 conserves ½Li²+q²/2C to 2.6e-5, and Henry's pre-1842 rival — aperiodic discharge, frequency-flat Ohmic response — is rejected structurally (599 current reversals vs predicted 0; 15.5× selectivity at 5% detuning vs predicted 1.0, which is why a dial can tune ONE station); module honesty debt retired: the on-screen panel's closed-form Lorentzian sweep replaced by the same ODE pipeline, pinned float-exact by gate M (screen 1.0066 MHz = this seed's disclosed ±1.5% read)

Method

The generator is ONE line of physics: L·q̈ + R·q̇ + q/C = V₀cos ωt (Kirchhoff's voltage law with V_L = L di/dt, V_C = q/C, V_R = Ri), integrated by fixed-step RK4. Non-circularity is structural: the time step dt = 2π√(LC)/80 is a unit combination of the inputs (the emwave Δt = S·Δx·√(μ₀ε₀) pattern — a scale, not the answer's location); the sweep window is centred on the circuit's own MEASURED free-ring frequency (kick the capacitor, least-squares the charge zero-crossing times); and f₀ is read as the bisected zero of the lock-in current phase — the drive frequency where the simulated current runs exactly in phase with the source. The resonance curve is a 121-point warm-start swept measurement of the lock-in amplitude |I|(f); the flat-peak-safe estimator is one least-squares parabola on the INVERSE-SQUARE curve 1/|I|² (near-exactly parabolic in f where |I| itself is quartically flat — the Malus/blackbody flat-peak lesson applied), whose vertex, level and level-doubling points give f₀, the peak and the half-power Δf in a single fit. 24 seeds re-read the same swept curve with ±1.5% uniform reading noise (the module's disclosed instrument class). Real bench: an AM-radio tuned tank, L = 250 µH, C = 100 pF, R = 10 Ω → f₀ ≈ 1.0066 MHz, Q ≈ 158, Δf ≈ 6.4 kHz < 10 kHz AM channel spacing. 13 gates in scripts/rlc-derisk.mjs (~1.3 s); tamper ⇒ exit 1. ?world=rlc.

Measurements, controls & cross-checks

Recovered se

3.4

Worst seed rel error

3.5400e-5

Noiseless floor

Rel
-3.1500e-7
Convergence
×17 shrink at 160 steps/cycle (1.86e-8) — 4th-order RK4: the residual is discretization, the limit is Thomson's f₀
Note
phase-zero bisection of the lock-in current quadratures; the same −3.15e-7 floor appears at every R and L (common-mode), so it cancels exactly in all slope gates

Emergent peak anatomy

Q recovered
158.1
Q known
158.11388
Q rel
2.0100e-5
Bandwidth khz
6.37
Peak amp vs V0overR rel
3.1300e-5
Note
Q = f₀/Δf off the swept curve matches (1/R)√(L/C) and the peak current matches V₀/R — reactances cancel at resonance; Δf = 6.4 kHz < 10 kHz AM spacing is WHY a dial separates stations

Scaling

F0 vs L slope
-0.5
F0 vs C slope
-0.5
Slope printed
−0.500000 over ×6.25 sweeps in each of L and C
R independence spread
2.6700e-9
Note
f₀ tracks L^−½ and C^−½ across the sweep yet does not move with R over 2.5–160 Ω (spread 2.7e-9) — the current phase-zero is set by L and C alone, exactly as Thomson's formula demands

Two resonances

Charge peak over f0
0.7071058
Expected
0.70710678
Phase zero shift at Q1
3.0700e-7
Note
at Q = 1 the CHARGE (capacitor-voltage) amplitude peaks at f₀√(1−1/(2Q²)) = f₀/√2 while the current phase-zero stays pinned at f₀ — voltage resonance and current resonance are different frequencies, an emergent split never coded

Damped ring

Q2 ratio
0.9682456
Q2 expected
0.96824584
Real tank shift rel
-5.0000e-6
Real tank residual rel
3.2000e-7
Note
the free ring runs at f₀√(1−1/(4Q²)): √15/4 at Q = 2, and even the real tank's tiny −5.0e-6 damped shift is RESOLVED against the 3e-7 integration floor

Energy

R0 drift rel
2.6100e-5
Slosh
max E_L = max E_C = E₀ to 1e-5
Note
with R = 0 the integrated loop conserves ½Li² + q²/2C over 100 cycles (drift = RK4's 4th-order dissipation) and the energy sloshes WHOLLY between the coil's B-field and the capacitor's E-field

Rival aperiodic ohm

Rival
the pre-1842 aperiodic-discharge / no-reactance view: a capacitor discharging through a conductor yields a one-directional decaying current (RC relaxation, zero oscillations), and a driven circuit is just Ohm's law — the same current at every frequency
Measured ring reversals
599
Rival predicted reversals
0
Measured selectivity at 5pct
15.47
Rival predicted selectivity
1
Note
the SAME integrated loop rejects the rival twice and structurally: the kicked circuit reverses current sign 599 times in 300 µs (Henry's 1842 reversed-magnetization observation, Thomson's 1853 explanation), and the driven response is 15.5× larger on resonance than 5% off it — a no-reactance radio could never tune

What it reduces to

Thomson's 1853 oscillation frequency f₀ = 1/(2π√(LC)) and the series-resonance anatomy Q = (1/R)√(L/C), |I|peak = V₀/R, f_charge = f₀√(1−1/(2Q²)), f_ring = f₀√(1−1/(4Q²)) (Phil. Mag. 5, 393 (1853); Griffiths §7.1; Feynman II ch. 23 'Resonance'). Non-circular: L, C, R, V₀ enter ONLY as the bench's parts list; the recovery path contains no 1/√(LC), no Lorentzian, no Q — the integration step is a unit combination (emwave's Δt pattern), the sweep window comes from the circuit's own measured free ring, and every recovered number (f₀, Δf, Q, the charge/current split, the damped shift) is read off lock-in projections of the integrated current. The mechanical twin (?world=resonance) proved the driven-oscillator peak; this world proves the ELECTRICAL dictionary L↔m, 1/C↔k, R↔b lands on a real radio's dial: the recovered Δf = 6.4 kHz < 10 kHz AM channel spacing is the quantitative reason one station comes in alone. The decisive discriminator is structural: Henry's aperiodic rival predicts zero current reversals and unit selectivity; the same machinery measures 599 and 15.5.

Module systematics

The module's real-units panel was the dishonest piece: its _recover() sampled the closed-form Lorentzian |I|(f) = V₀/√(R²+(2πfL−1/(2πfC))²) — the very law under test — with noise, and read the peak by raw argmax on 4001 noisy points (a max-of-noise-biased estimator besides). THIS RUN REPLACED IT: the module now runs the identical first-principles pipeline as the oracle (free-ring bootstrap → 121-point warm-start RK4 sweep of the loop ODE → ±1.5% reading noise via its own mulberry32(0x5c1f) → inverse-square parabola), and gate M replays that pipeline verbatim, pinning the on-screen numbers float-exact: screen f₀ = 1.0066 MHz (1006572.19 Hz = −1.2e-5 off Thomson — this seed's disclosed single-read noise draw, ~1 SE of one ±1.5% sweep, not a bias: the 24-seed mean sits 1.77 SE from known), Q = 156 (true 158), L̂ = 250.006 µH, Δf = 6.44 kHz — verified live headless (vite preview + playwright, panel scrape). The dimensionless live view (glow handoff, sweeping marker on the drawn Lorentzian) remains an explicitly disclosed forward-model display; every number in the '—— real AM-radio tuned tank ——' block comes from the integrated ODE.

Notes

Rung climbed: no-oracle → validated + honest module (53 → 54 oracles). Tolerances from measured floors, never padded: noiseless 1e-6 vs measured 3.15e-7 (with the ×17 convergence gate proving it is discretization); MC gates 1e-5/4·SE/1e-4 vs measured 6.1e-6/1.77 SE/3.5e-5; Q 3% vs measured 2e-5; slopes ±1e-4 vs measured <1e-6 (common-mode floor cancels). ESTIMATOR LESSON (new, #13): a quadratic vertex on the AMPLITUDE of a Lorentzian-like peak is doubly biased — the quartic-flat top drags the fitted peak LEVEL ~1% low, which drags the half-power width ~5% wide (Q read 150 for 158) even after fixing the smoothed-level bias (Q 138). Fit the INVERSE-SQUARE curve instead: 1/|I|² is near-exactly parabolic in f for a series resonance, so ONE least-squares parabola reads f₀ (vertex), peak level AND Δf (level-doubling points) unbiased — Q landed at 2e-5 immediately. Corollary of the divide rule: inverting is safe here because every windowed point is ≥55% of peak. Two estimator fix attempts used on gate E (smoothed→vertex level, then inverse-square); zero physics fixes — every physics gate passed on first run. Tamper (known → 1.1 MHz): 6 gates FAIL, exit 1, recovery unchanged at 1006583.9; restored by hand. Scope: scripts/oracles/rlc.reference.json + scripts/rlc-derisk.mjs (new), src/modules/RLCResonanceModule.ts (recovery honesty), data/findings/rlc.json, fragment, loop-runs line — all world rlc; no shared files touched.

Confidence & reproduction

Confidence
high
Validation
derisk-pass
Re-run the check
npm run derisk -- rlc (scripts/rlc-derisk.mjs)
Oracle
scripts/oracles/rlc.reference.json

Sources

W. Thomson (Lord Kelvin), 'On Transient Electric Currents', Phil. Mag. 5, 393 (1853). J. Henry, Proc. Am. Phil. Soc. 2, 193 (1842). D. J. Griffiths, Introduction to Electrodynamics (4th ed.), §7.1; R. P. Feynman, The Feynman Lectures on Physics, Vol. II, ch. 23. AM broadcast channel spacing 10 kHz (ITU Region 2), band 535–1605 kHz.

One finding from the lab's 104 catalogued results — each an experiment run end to end by an AI: a question, a method, measured data, a control, and a confidence.