| Property | Pure R | Pure L | Pure C |
|---|---|---|---|
| Reactance/Impedance | R (ohm) | X_L = ωL = 2πfL | X_C = 1/(ωC) = 1/(2πfC) |
| Phase (I w.r.t. V) | In phase (φ = 0) | I lags V by 90° | I leads V by 90° |
| Mnemonic | — | ELI (E leads I in L) | ICE (I leads E in C) |
| Average Power | P = V_rms I_rms | P = 0 (wattless) | P = 0 (wattless) |
| Power Factor | cos φ = 1 | cos φ = 0 | cos φ = 0 |
| Frequency effect | R unchanged | (increases) | X_C ∝ 1/f (decreases) |
| Energy | Dissipated as heat | Stored in B-field, returned | Stored in E-field, returned |
| Phasor: V vs I | Parallel | V leads I by 90° | I leads V by 90° |
Key insight: Only R dissipates power. L and C store and return energy—no net consumption. In a series LCR circuit, all three are present and the phase angle is intermediate.