AC impedance & phasors worksheet with answers

Free printable AC impedance & phasors worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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1.Easy
230 V50 HzR = 10 ΩL = 50 mH

A series RL circuit is connected to a 230 V (rms), 50 Hz supply. Find the rms voltage VL across the inductor.

V = 230 V (rms)f = 50 HzR = 10 ΩL = 50 mH
VL = V
2.Easy
10 V60 HzR = 15 ΩL = 100 mH

A series RL circuit is connected to a 10 V (rms), 60 Hz supply. Find the magnitude of the impedance |Z|.

V = 10 V (rms)f = 60 HzR = 15 ΩL = 100 mH
|Z| = Ω
3.Medium
Vf0​ = 60 HzRL = ?C = 22 µF

A series RLC circuit with C = 22 µF must resonate at 60 Hz. Find the inductance L needed.

f0 = 60 HzC = 22 µF
L = mH
4.Medium
230 V500 HzR = 25 ΩL = 150 mHC = 47 µF

A series RLC circuit is connected to a 230 V (rms), 500 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 230 V (rms)f = 500 HzR = 25 ΩL = 150 mHC = 47 µF
φ = °
5.Hard
5 Vf0​R = 15 ΩL = 50 mHC = 10 µF

A series RLC circuit is driven by a 5 V (rms) source whose frequency is set to the resonant frequency of the circuit. Find the rms voltage VL across the inductor.

V = 5 V (rms)R = 15 ΩL = 50 mHC = 10 µF
VL = V
6.Hard
24 Vf0​R = 10 ΩL = 50 mHC = 2.2 µF

A series RLC circuit is driven by a 24 V (rms) source whose frequency is set to the resonant frequency of the circuit. Find the rms voltage VL across the inductor.

V = 24 V (rms)R = 10 ΩL = 50 mHC = 2.2 µF
VL = V

Answer key

  1. 1. VL = 194 V
  2. 2. |Z| = 40.57 Ω
  3. 3. L = 319.8 mH
  4. 4. φ = 86.92 °
  5. 5. VL = 23.57 V
  6. 6. VL = 361.8 V

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