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 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 = 10 ΩL = 50 mH
I = A
2.Easy
100 V100 HzR = 100 ΩC = 2.2 µF

A series RC circuit is connected to a 100 V (rms), 100 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 100 V (rms)f = 100 HzR = 100 ΩC = 2.2 µF
φ = °
3.Medium
12 V200 HzR = 30 ΩL = 20 mHC = 47 µFI

A series RLC circuit is connected to a 12 V (rms), 200 Hz supply. Find the power factor cos φ of the circuit.

V = 12 V (rms)f = 200 HzR = 30 ΩL = 20 mHC = 47 µF
cos φ =
4.Medium
10 V60 HzR = 10 ΩL = 150 mHC = 100 µFI

A series RLC circuit is connected to a 10 V (rms), 60 Hz supply. Find the rms current I.

V = 10 V (rms)f = 60 HzR = 10 ΩL = 150 mHC = 100 µF
I = A
5.Hard
50 V500 HzR = 50 ΩL = 50 mHC = 2.2 µF+−VC​

A series RLC circuit is connected to a 50 V (rms), 500 Hz supply. Find the rms voltage VC across the capacitor.

V = 50 V (rms)f = 500 HzR = 50 ΩL = 50 mHC = 2.2 µF
VC = V
6.Hard
5 Vf0​R = 5 ΩL = 100 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 = 5 ΩL = 100 mHC = 4.7 µF
VL = V

Answer key

  1. 1. I = 12.35 A
  2. 2. φ = −82.13 °
  3. 3. cos φ = 0.9646
  4. 4. I = 0.316 A
  5. 5. VC = 140.4 V
  6. 6. VL = 145.9 V

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