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
10 V60 HzR = 25 ΩL = 20 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 = 25 ΩL = 20 mH
|Z| = Ω
2.Easy
230 V50 HzR = 50 ΩL = 150 mHI

A series RL circuit is connected to a 230 V (rms), 50 Hz supply. Find the rms current I.

V = 230 V (rms)f = 50 HzR = 50 ΩL = 150 mH
I = A
3.Medium
50 V60 HzR = 40 ΩL = 200 mHC = 22 µFI

A series RLC circuit is connected to a 50 V (rms), 60 Hz supply. Find the power factor cos φ of the circuit.

V = 50 V (rms)f = 60 HzR = 40 ΩL = 200 mHC = 22 µF
cos φ =
4.Medium
100 V200 HzR = 80 ΩL = 150 mHC = 100 µFI

A series RLC circuit is connected to a 100 V (rms), 200 Hz supply. Find the power factor cos φ of the circuit.

V = 100 V (rms)f = 200 HzR = 80 ΩL = 150 mHC = 100 µF
cos φ =
5.Hard
50 V200 HzR = 10 ΩL = 250 mHC = 2.2 µF

A series RLC circuit is connected to a 50 V (rms), 200 Hz supply. Find the resonant frequency f0 of the circuit.

V = 50 V (rms)f = 200 HzR = 10 ΩL = 250 mHC = 2.2 µF
f0 = Hz
6.Hard
2 Vf0​R = 50 ΩL = 5 mHC = 0.47 µF

A series RLC circuit is driven by a 2 V (rms) source whose frequency is set to the resonant frequency of the circuit. Find the rms voltage VL across the inductor.

V = 2 V (rms)R = 50 ΩL = 5 mHC = 0.47 µF
VL = V

Answer key

  1. 1. |Z| = 26.11 Ω
  2. 2. I = 3.348 A
  3. 3. cos φ = 0.6629
  4. 4. cos φ = 0.4051
  5. 5. f0 = 214.6 Hz
  6. 6. VL = 4.126 V

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