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 V60 HzR = 20 ΩL = 250 mH

A series RL circuit is connected to a 24 V (rms), 60 Hz supply. Find the magnitude of the impedance |Z|.

V = 24 V (rms)f = 60 HzR = 20 ΩL = 250 mH
|Z| = Ω
2.Easy
24 V50 HzR = 10 ΩL = 50 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 = 10 ΩL = 50 mH
I = A
3.Medium
Vf0​ = 2000 HzRL = ?C = 47 µF

A series RLC circuit with C = 47 µF must resonate at 2000 Hz. Find the inductance L needed.

f0 = 2000 HzC = 47 µF
L = mH
4.Medium
230 V60 HzR = 50 ΩL = 100 mHI

A resistor and an inductor are connected in parallel across a 230 V (rms), 60 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 230 V (rms)f = 60 HzR = 50 ΩL = 100 mH
φ = °
5.Hard
VfR = 2 ΩL = 20 mHC = 1 µF

A series RLC circuit has R = 2 Ω, L = 20 mH and C = 1 µF. Find its bandwidth B (the width of the band between the half-power frequencies), in Hz.

R = 2 ΩL = 20 mHC = 1 µF
B = Hz
6.Hard
24 Vf0​R = 10 ΩL = 200 mHC = 1 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 = 200 mHC = 1 µF
VL = V

Answer key

  1. 1. |Z| = 96.35 Ω
  2. 2. I = 1.289 A
  3. 3. L = 0.1347 mH
  4. 4. φ = 52.98 °
  5. 5. B = 15.92 Hz
  6. 6. VL = 1073 V

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