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 = 100 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 = 100 mH
VL = V
2.Easy
120 V50 HzR = 60 ΩL = 100 mHI

A series RL circuit is connected to a 120 V (rms), 50 Hz supply. Find the rms current I.

V = 120 V (rms)f = 50 HzR = 60 ΩL = 100 mH
I = A
3.Medium
100 V1000 HzR = 80 ΩL = 100 mHC = 4.7 µFI

A series RLC circuit is connected to a 100 V (rms), 1000 Hz supply. Find the rms current I.

V = 100 V (rms)f = 1000 HzR = 80 ΩL = 100 mHC = 4.7 µF
I = A
4.Medium
Vf0​ = 1000 HzRL = 2 mHC = ?

A series RLC circuit with L = 2 mH must resonate at 1000 Hz. Find the capacitance C needed.

f0 = 1000 HzL = 2 mH
C = µF
5.Hard
12 V100 HzR = 10 ΩL = 250 mHC = 100 µF

A series RLC circuit is connected to a 12 V (rms), 100 Hz supply. Find the resonant frequency f0 of the circuit.

V = 12 V (rms)f = 100 HzR = 10 ΩL = 250 mHC = 100 µF
f0 = Hz
6.Hard
24 V50 HzR = 50 ΩL = 20 mHC = 47 µF+−VC​

A series RLC circuit is connected to a 24 V (rms), 50 Hz supply. Find the rms voltage VC across the capacitor.

V = 24 V (rms)f = 50 HzR = 50 ΩL = 20 mHC = 47 µF
VC = V

Answer key

  1. 1. VL = 194 V
  2. 2. I = 1.772 A
  3. 3. I = 0.1667 A
  4. 4. C = 12.67 µF
  5. 5. f0 = 31.83 Hz
  6. 6. VC = 20.52 V

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