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 V60 HzR = 30 ΩL = 20 mH

A series RL circuit is connected to a 120 V (rms), 60 Hz supply. Find the magnitude of the impedance |Z|.

V = 120 V (rms)f = 60 HzR = 30 ΩL = 20 mH
|Z| = Ω
2.Easy
120 V100 HzR = 220 ΩC = 100 µF

A series RC circuit is connected to a 120 V (rms), 100 Hz supply. Find the magnitude of the impedance |Z|.

V = 120 V (rms)f = 100 HzR = 220 ΩC = 100 µF
|Z| = Ω
3.Medium
Vf0​ = 200 HzRL = ?C = 2.2 µF

A series RLC circuit with C = 2.2 µF must resonate at 200 Hz. Find the inductance L needed.

f0 = 200 HzC = 2.2 µF
L = mH
4.Medium
Vf0​ = 200 HzRL = ?C = 1 µF

A series RLC circuit with C = 1 µF must resonate at 200 Hz. Find the inductance L needed.

f0 = 200 HzC = 1 µF
L = mH
5.Hard
100 V500 HzR = 30 ΩL = 100 mHC = 22 µF+−VC​

A series RLC circuit is connected to a 100 V (rms), 500 Hz supply. Find the rms voltage VC across the capacitor.

V = 100 V (rms)f = 500 HzR = 30 ΩL = 100 mHC = 22 µF
VC = V
6.Hard
5 Vf0​R = 20 ΩL = 10 mHC = 4.7 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 = 20 ΩL = 10 mHC = 4.7 µF
VL = V

Answer key

  1. 1. |Z| = 30.93 Ω
  2. 2. |Z| = 220.6 Ω
  3. 3. L = 287.8 mH
  4. 4. L = 633.3 mH
  5. 5. VC = 4.804 V
  6. 6. VL = 11.53 V

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