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 = 150 mH

A series RL circuit is connected to a 120 V (rms), 50 Hz supply. Find the magnitude of the impedance |Z|.

V = 120 V (rms)f = 50 HzR = 10 ΩL = 150 mH
|Z| = Ω
2.Easy
50 V60 HzR = 80 ΩL = 150 mH

A series RL circuit is connected to a 50 V (rms), 60 Hz supply. Find the rms voltage VL across the inductor.

V = 50 V (rms)f = 60 HzR = 80 ΩL = 150 mH
VL = V
3.Medium
100 V100 HzR = 40 ΩL = 20 mHC = 100 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 = 20 mHC = 100 µF
φ = °
4.Medium
10 V200 HzR = 80 ΩL = 100 mHC = 22 µFI

A series RLC circuit is connected to a 10 V (rms), 200 Hz supply. Find the rms current I.

V = 10 V (rms)f = 200 HzR = 80 ΩL = 100 mHC = 22 µF
I = A
5.Hard
5 Vf0​R = 50 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 = 50 ΩL = 10 mHC = 0.22 µF
VL = V
6.Hard
230 V200 HzR1​ = 20 ΩR2​ = 80 ΩC = 4.7 µFI

A resistor R1 is connected in series with a parallel combination of R2 and a capacitor C, across a 230 V (rms), 200 Hz supply. Find the rms current I.

V = 230 V (rms)f = 200 HzR1 = 20 ΩR2 = 80 ΩC = 4.7 µF
I = A

Answer key

  1. 1. |Z| = 48.17 Ω
  2. 2. VL = 28.86 V
  3. 3. φ = −4.786 °
  4. 4. I = 0.08331 A
  5. 5. VL = 21.32 V
  6. 6. I = 2.533 A

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