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 = 100 ΩL = 200 mH

A series RL circuit is connected to a 230 V (rms), 50 Hz supply. Find the magnitude of the impedance |Z|.

V = 230 V (rms)f = 50 HzR = 100 ΩL = 200 mH
|Z| = Ω
2.Easy
Vf = ?L = 500 mH

At what frequency f does a 500 mH inductor have a reactance of 20 Ω?

L = 500 mHXL = 20 Ω
f = Hz
3.Medium
12 V200 HzR = 40 ΩL = 200 mHC = 4.7 µF

A series RLC circuit is connected to a 12 V (rms), 200 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 12 V (rms)f = 200 HzR = 40 ΩL = 200 mHC = 4.7 µF
φ = °
4.Medium
230 V500 HzR = 25 ΩL = 150 mHC = 10 µF

A series RLC circuit is connected to a 230 V (rms), 500 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 230 V (rms)f = 500 HzR = 25 ΩL = 150 mHC = 10 µF
φ = °
5.Hard
5 Vf0​R = 2 ΩL = 20 mHC = 2.2 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 = 2 ΩL = 20 mHC = 2.2 µF
VL = V
6.Hard
120 V100 HzR = 80 ΩL = 200 mHC = 22 µFI

A series RLC circuit is connected to a 120 V (rms), 100 Hz supply. Find the rms current I.

V = 120 V (rms)f = 100 HzR = 80 ΩL = 200 mHC = 22 µF
I = A

Answer key

  1. 1. |Z| = 118.1 Ω
  2. 2. f = 6.366 Hz
  3. 3. φ = 64 °
  4. 4. φ = 86.74 °
  5. 5. VL = 238.4 V
  6. 6. I = 1.248 A

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