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
12 V50 HzR = 80 ΩL = 150 mH

A series RL circuit is connected to a 12 V (rms), 50 Hz supply. Find the rms voltage VL across the inductor.

V = 12 V (rms)f = 50 HzR = 80 ΩL = 150 mH
VL = V
2.Easy
V1000 HzC = 1 µF

Find the reactance XC of a 1 µF capacitor at 1000 Hz.

C = 1 µFf = 1000 Hz
XC = Ω
3.Medium
24 V500 HzR = 40 ΩL = 250 mHC = 1 µFI

A series RLC circuit is connected to a 24 V (rms), 500 Hz supply. Find the rms current I.

V = 24 V (rms)f = 500 HzR = 40 ΩL = 250 mHC = 1 µF
I = A
4.Medium
Vf0​ = 200 HzRL = 20 mHC = ?

A series RLC circuit with L = 20 mH must resonate at 200 Hz. Find the capacitance C needed.

f0 = 200 HzL = 20 mH
C = µF
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
230 V100 HzR = 40 ΩL = 200 mHC = 4.7 µFI

A series RLC circuit is connected to a 230 V (rms), 100 Hz supply. Find the rms current I.

V = 230 V (rms)f = 100 HzR = 40 ΩL = 200 mHC = 4.7 µF
I = A

Answer key

  1. 1. VL = 6.09 V
  2. 2. XC = 159.2 Ω
  3. 3. I = 0.05119 A
  4. 4. C = 31.66 µF
  5. 5. B = 15.92 Hz
  6. 6. I = 1.061 A

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