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
24 V50 HzR = 20 ΩL = 20 mHI

A series RL circuit is connected to a 24 V (rms), 50 Hz supply. Find the rms current I.

V = 24 V (rms)f = 50 HzR = 20 ΩL = 20 mH
I = A
2.Easy
10 V50 HzR = 40 ΩL = 200 mH

A series RL circuit is connected to a 10 V (rms), 50 Hz supply. Find the magnitude of the impedance |Z|.

V = 10 V (rms)f = 50 HzR = 40 ΩL = 200 mH
|Z| = Ω
3.Medium
12 V500 HzR = 25 ΩL = 150 mHC = 4.7 µF

A series RLC circuit is connected to a 12 V (rms), 500 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 12 V (rms)f = 500 HzR = 25 ΩL = 150 mHC = 4.7 µF
φ = °
4.Medium
50 V500 HzR = 50 ΩL = 100 mHC = 22 µF

A series RLC circuit is connected to a 50 V (rms), 500 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 50 V (rms)f = 500 HzR = 50 ΩL = 100 mHC = 22 µF
φ = °
5.Hard
VfR = 2 ΩL = 1 mHC = 2.2 µF

A series RLC circuit has R = 2 Ω, L = 1 mH and C = 2.2 µF. Find its quality factor Q at resonance.

R = 2 ΩL = 1 mHC = 2.2 µF
Q =
6.Hard
5 Vf0​R = 10 ΩL = 10 mHC = 0.22 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 = 10 ΩL = 10 mHC = 0.22 µF
VL = V

Answer key

  1. 1. I = 1.145 A
  2. 2. |Z| = 74.48 Ω
  3. 3. φ = 86.45 °
  4. 4. φ = 80.53 °
  5. 5. Q = 10.66
  6. 6. VL = 106.6 V

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