A series circuit has R = 12 Ω, XL = 25 Ω and XC = 9 Ω at the supply frequency. With 120 V RMS applied, what are its current and power factor?
Check your answer
Net reactance is 25 − 9 = 16 Ω. The impedance magnitude is √(12² + 16²) = 20 Ω, so current is 6 A RMS. Power factor is 12 / 20 = 0.6 lagging. Real power is 120 × 6 × 0.6 = 432 W.