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
120 V50 HzR = 60 ΩL = 100 mH

A series RL circuit is connected to a 120 V (rms), 50 Hz supply. Find the magnitude of the impedance |Z|.

V = 120 V (rms)f = 50 HzR = 60 ΩL = 100 mH
|Z| = Ω
2.Easy
100 V50 HzR = 20 ΩL = 250 mH

A series RL circuit is connected to a 100 V (rms), 50 Hz supply. Find the magnitude of the impedance |Z|.

V = 100 V (rms)f = 50 HzR = 20 ΩL = 250 mH
|Z| = Ω
3.Medium
120 V100 HzR = 15 ΩL = 200 mHC = 100 µFI

A series RLC circuit is connected to a 120 V (rms), 100 Hz supply. Find the power factor cos φ of the circuit.

V = 120 V (rms)f = 100 HzR = 15 ΩL = 200 mHC = 100 µF
cos φ =
4.Medium
50 V200 HzR = 25 ΩL = 200 mHC = 4.7 µFI

A series RLC circuit is connected to a 50 V (rms), 200 Hz supply. Find the rms current I.

V = 50 V (rms)f = 200 HzR = 25 ΩL = 200 mHC = 4.7 µF
I = A
5.Hard
24 Vf0​R = 20 ΩL = 5 mHC = 0.22 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 = 20 ΩL = 5 mHC = 0.22 µF
VL = V
6.Hard
10 V500 HzR = 60 ΩL = 100 mHC = 2.2 µFI

A series RLC circuit is connected to a 10 V (rms), 500 Hz supply. Find the rms current I.

V = 10 V (rms)f = 500 HzR = 60 ΩL = 100 mHC = 2.2 µF
I = A

Answer key

  1. 1. |Z| = 67.73 Ω
  2. 2. |Z| = 81.05 Ω
  3. 3. cos φ = 0.1354
  4. 4. I = 0.5832 A
  5. 5. VL = 180.9 V
  6. 6. I = 0.05562 A

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