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 = 50 ΩL = 250 mH

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

V = 120 V (rms)f = 100 HzR = 50 ΩL = 250 mH
VR = V
2.Easy
230 V100 HzR = 30 ΩL = 200 mH

A series RL circuit is connected to a 230 V (rms), 100 Hz supply. Find the rms voltage VL across the inductor.

V = 230 V (rms)f = 100 HzR = 30 ΩL = 200 mH
VL = V
3.Medium
Vf0​ = 50 HzRL = 5 mHC = ?

A series RLC circuit with L = 5 mH must resonate at 50 Hz. Find the capacitance C needed.

f0 = 50 HzL = 5 mH
C = µF
4.Medium
12 V60 HzR = 30 ΩL = 100 mHC = 4.7 µFI

A series RLC circuit is connected to a 12 V (rms), 60 Hz supply. Find the rms current I.

V = 12 V (rms)f = 60 HzR = 30 ΩL = 100 mHC = 4.7 µF
I = A
5.Hard
24 V50 HzR1​ = 40 ΩR2​ = 80 ΩC = 47 µFI

A resistor R1 is connected in series with a parallel combination of R2 and a capacitor C, across a 24 V (rms), 50 Hz supply. Find the rms current I.

V = 24 V (rms)f = 50 HzR1 = 40 ΩR2 = 80 ΩC = 47 µF
I = A
6.Hard
100 V500 HzR = 60 ΩL = 200 mHC = 10 µF+−VC​

A series RLC circuit is connected to a 100 V (rms), 500 Hz supply. Find the rms voltage VC across the capacitor.

V = 100 V (rms)f = 500 HzR = 60 ΩL = 200 mHC = 10 µF
VC = V

Answer key

  1. 1. VR = 36.4 V
  2. 2. VL = 223.7 V
  3. 3. C = 2026 µF
  4. 4. I = 0.02275 A
  5. 5. I = 0.288 A
  6. 6. VC = 5.31 V

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