• Tags: strategy, phasor, calculation
• Difficulty: Advanced

Step 1: Identify circuit type (pure R/L/C, series LR/CR/LCR, parallel). Step 2: Calculate reactances: $X_L$ = omegaL, $X_C$ = $\frac{1}{omega*C}$. Step 3: Find impedance Z and phase angle phi. Step 4: Calculate current I = $\frac{V}{Z}$. Step 5: Find individual voltages: $V_R$ = IR, $V_L$ = $IX_L$, $V_C$ = $IX_C$. Step 6: Calculate power: P = $I^2$R = VIcos(phi). Common pitfalls: (1) Adding voltages algebraically instead of using phasor addition — $V_R$ + $V_L$ + $V_C$ does NOT equal $V_{source}$. (2) Confusing peak and RMS values — power formulas use RMS. (3) In resonance problems, forgetting that $V_L$ and $V_C$ can individually exceed $V_{source}$. (4) For parallel circuits, add admittances (Y = 1/Z) instead of impedances. (5) At resonance in a parallel LC circuit, impedance is maximum (not minimum like series).