Trap 1 — Resonance impedance: The most common error. Z at resonance = R (minimum), NOT zero. Z = √($R^{2}$ + 0^{2}) = R. Current is maximum = V/R. Only net REACTANCE is zero.

Trap 2 — Transformer current ratio: Students write I_s/I_p = N_s/N_p (same as voltage). The correct relation is I_s/I_p = N_p/N_s (INVERSE). High voltage → low current. "Turns up, voltage up, current DOWN."

Trap 3 — RMS vs Mean: V_rms = $V_{0}$/√2 ≈ 0.707$V_{0}$ (for power). V_mean = 2$V_{0}$/π ≈ 0.637$V_{0}$ (half-cycle average for rectification). These are NOT equal. V_rms > V_mean.

Trap 4 — EMF zero when flux is zero: False. EMF = −dΦ/dt. EMF is maximum when flux is zero (changing fastest). EMF is zero when flux is maximum (rate of change = 0).

Trap 5 — Arithmetic sum of LCR voltages: V_supply ≠ V_R + V_L + V_C. Must use phasor sum: V = √(V_$R^{2}$ + (V_L − V_C)^{2}).

Trap 6 — Lamination reduces hysteresis: Wrong. Lamination reduces EDDY CURRENT losses (breaks current paths). HYSTERESIS loss is reduced by soft iron or silicon steel (narrow B-H loop).

Trap 7 — Motional EMF formula always Bvl: Only valid when v, B, l are mutually perpendicular. If there is an angle between v and B: ε = Bvl sin θ.

Trap 8 — Pure L/C consume power: They consume zero average power. cos φ = 0 for φ = 90°. Energy is stored and returned each half-cycle.

Trap 9 — Step-up transformer increases both V and I: Conservation of energy forbids this. P = VI = constant. V increases → I decreases proportionally.

Trap 10 — Average of sinusoid over full cycle: ∫_{0}^{2}π sin(ωt) dt = 0. Full-cycle average of V is zero. Only RMS values are meaningful for power.