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 = 20 ΩL = 50 mH

A series RL circuit is connected to a 230 V (rms), 50 Hz supply. Find the rms voltage VL across the inductor.

V = 230 V (rms)f = 50 HzR = 20 ΩL = 50 mH
VL = V
2.Easy
50 V100 HzR = 60 ΩL = 200 mH

A series RL circuit is connected to a 50 V (rms), 100 Hz supply. Find the rms voltage VL across the inductor.

V = 50 V (rms)f = 100 HzR = 60 ΩL = 200 mH
VL = V
3.Medium
230 V50 HzR = 40 ΩL = 150 mHC = 10 µFI

A series RLC circuit is connected to a 230 V (rms), 50 Hz supply. Find the rms current I.

V = 230 V (rms)f = 50 HzR = 40 ΩL = 150 mHC = 10 µF
I = A
4.Medium
Vf0​ = 5000 HzRL = ?C = 22 µF

A series RLC circuit with C = 22 µF must resonate at 5000 Hz. Find the inductance L needed.

f0 = 5000 HzC = 22 µF
L = mH
5.Hard
VfR = 10 ΩL = 20 mHC = 0.1 µF

A series RLC circuit has R = 10 Ω, L = 20 mH and C = 0.1 µF. Find its bandwidth B (the width of the band between the half-power frequencies), in Hz.

R = 10 ΩL = 20 mHC = 0.1 µF
B = Hz
6.Hard
24 V100 HzR = 50 ΩL = 100 mHC = 47 µFI

A series RLC circuit is connected to a 24 V (rms), 100 Hz supply. Find the rms current I.

V = 24 V (rms)f = 100 HzR = 50 ΩL = 100 mHC = 47 µF
I = A

Answer key

  1. 1. VL = 142.1 V
  2. 2. VL = 45.12 V
  3. 3. I = 0.839 A
  4. 4. L = 0.04606 mH
  5. 5. B = 79.58 Hz
  6. 6. I = 0.4153 A

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