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
100 V60 HzR = 30 ΩL = 150 mH

A series RL circuit is connected to a 100 V (rms), 60 Hz supply. Find the rms voltage VR across the resistor.

V = 100 V (rms)f = 60 HzR = 30 ΩL = 150 mH
VR = V
2.Easy
12 V50 HzR = 60 ΩL = 20 mH

A series RL circuit is connected to a 12 V (rms), 50 Hz supply. Find the magnitude of the impedance |Z|.

V = 12 V (rms)f = 50 HzR = 60 ΩL = 20 mH
|Z| = Ω
3.Medium
Vf0​ = 60 HzRL = 50 mHC = ?

A series RLC circuit with L = 50 mH must resonate at 60 Hz. Find the capacitance C needed.

f0 = 60 HzL = 50 mH
C = µF
4.Medium
Vf0​ = 2000 HzRL = ?C = 2.2 µF

A series RLC circuit with C = 2.2 µF must resonate at 2000 Hz. Find the inductance L needed.

f0 = 2000 HzC = 2.2 µF
L = mH
5.Hard
50 V50 HzR = 80 ΩL = 150 mHC = 47 µFI

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

V = 50 V (rms)f = 50 HzR = 80 ΩL = 150 mHC = 47 µF
I = A
6.Hard
10 V100 HzR = 30 ΩL = 200 mHC = 47 µF+−VC​

A series RLC circuit is connected to a 10 V (rms), 100 Hz supply. Find the rms voltage VC across the capacitor.

V = 10 V (rms)f = 100 HzR = 30 ΩL = 200 mHC = 47 µF
VC = V

Answer key

  1. 1. VR = 46.86 V
  2. 2. |Z| = 60.33 Ω
  3. 3. C = 140.7 µF
  4. 4. L = 2.878 mH
  5. 5. I = 0.6053 A
  6. 6. VC = 3.506 V

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