• $summary_{type}$: revision
• $word_{count}$: 160

Pure resistor: I in phase with V. Impedance = R (frequency-independent). Power = $V^2$/R. Pure inductor: current lags voltage by pi/2 (ELI). Impedance = $X_L$ = omega*L. Power = 0 (wattless). At DC: $X_L$ = 0 (short circuit). At high f: $X_L$ -> infinity (open). Pure capacitor: current leads voltage by pi/2 (ICE). Impedance = $X_C$ = $\frac{1}{omega*C}$. Power = 0 (wattless). At DC: $X_C$ -> infinity (open circuit). At high f: $X_C$ -> 0 (short). These opposite frequency responses of L and C are the basis of resonance — at some frequency, their effects cancel perfectly. Phasor representation: $V_R$ along I, $V_L$ 90 degrees ahead of I, $V_C$ 90 degrees behind I. The mnemonic ELI the ICE man captures all phase relationships. Energy storage: inductor stores $LI^2$/2 (magnetic), capacitor stores $CV^2$/2 (electric).