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 V100 HzR = 15 ΩL = 150 mH

A series RL circuit is connected to a 120 V (rms), 100 Hz supply. Find the rms voltage VL across the inductor.

V = 120 V (rms)f = 100 HzR = 15 ΩL = 150 mH
VL = V
2.Easy
V400 HzL = 5 mH

Find the reactance XL of a 5 mH inductor at 400 Hz.

L = 5 mHf = 400 Hz
XL = Ω
3.Medium
230 V60 HzR = 50 ΩL = 50 mHC = 47 µFI

A series RLC circuit is connected to a 230 V (rms), 60 Hz supply. Find the real power P taken from the supply.

V = 230 V (rms)f = 60 HzR = 50 ΩL = 50 mHC = 47 µF
P = W
4.Medium
10 V50 HzR = 80 ΩL = 150 mHC = 2.2 µFI

A series RLC circuit is connected to a 10 V (rms), 50 Hz supply. Find the rms current I.

V = 10 V (rms)f = 50 HzR = 80 ΩL = 150 mHC = 2.2 µF
I = A
5.Hard
2 Vf0​R = 20 ΩL = 200 mHC = 2.2 µF

A series RLC circuit is driven by a 2 V (rms) source whose frequency is set to the resonant frequency of the circuit. Find the rms voltage VL across the inductor.

V = 2 V (rms)R = 20 ΩL = 200 mHC = 2.2 µF
VL = V
6.Hard
VfR = 50 ΩL = 1 mHC = 0.022 µF

A series RLC circuit has R = 50 Ω, L = 1 mH and C = 0.022 µF. Find its quality factor Q at resonance.

R = 50 ΩL = 1 mHC = 0.022 µF
Q =

Answer key

  1. 1. VL = 118.5 V
  2. 2. XL = 12.57 Ω
  3. 3. P = 676 W
  4. 4. I = 0.007133 A
  5. 5. VL = 30.15 V
  6. 6. Q = 4.264

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