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 = 10 ΩL = 200 mHI

A series RL circuit is connected to a 120 V (rms), 50 Hz supply. Find the rms current I.

V = 120 V (rms)f = 50 HzR = 10 ΩL = 200 mH
I = A
2.Easy
100 V50 HzR = 40 ΩL = 20 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 = 40 ΩL = 20 mH
|Z| = Ω
3.Medium
24 V100 HzR = 20 ΩC = 22 µFI

A resistor and a capacitor are connected in parallel across a 24 V (rms), 100 Hz supply. Find the rms current I.

V = 24 V (rms)f = 100 HzR = 20 ΩC = 22 µF
I = A
4.Medium
100 V100 HzR = 40 ΩL = 50 mHC = 47 µF

A series RLC 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 = 40 ΩL = 50 mHC = 47 µF
φ = °
5.Hard
24 Vf0​R = 10 ΩL = 5 mHC = 4.7 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 = 10 ΩL = 5 mHC = 4.7 µF
VL = V
6.Hard
VfR = 5 ΩL = 1 mHC = 0.022 µF

A series RLC circuit has R = 5 Ω, L = 1 mH and C = 0.022 µF. Find its quality factor Q at resonance.

R = 5 ΩL = 1 mHC = 0.022 µF
Q =

Answer key

  1. 1. I = 1.886 A
  2. 2. |Z| = 40.49 Ω
  3. 3. I = 1.245 A
  4. 4. φ = −3.5 °
  5. 5. VL = 78.28 V
  6. 6. Q = 42.64

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