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
10 V50 HzR = 20 ΩL = 250 mH

A series RL circuit is connected to a 10 V (rms), 50 Hz supply. Find the magnitude of the impedance |Z|.

V = 10 V (rms)f = 50 HzR = 20 ΩL = 250 mH
|Z| = Ω
2.Easy
230 V50 HzR = 20 ΩL = 150 mHI

A series RL circuit is connected to a 230 V (rms), 50 Hz supply. Find the rms current I.

V = 230 V (rms)f = 50 HzR = 20 ΩL = 150 mH
I = A
3.Medium
230 V1000 HzR = 25 ΩL = 20 mHC = 100 µFI

A series RLC circuit is connected to a 230 V (rms), 1000 Hz supply. Find the rms current I.

V = 230 V (rms)f = 1000 HzR = 25 ΩL = 20 mHC = 100 µF
I = A
4.Medium
Vf0​ = 2000 HzRL = ?C = 0.1 µF

A series RLC circuit with C = 0.1 µF must resonate at 2000 Hz. Find the inductance L needed.

f0 = 2000 HzC = 0.1 µF
L = mH
5.Hard
12 V100 HzR = 80 ΩL = 20 mHC = 4.7 µF+−VC​

A series RLC circuit is connected to a 12 V (rms), 100 Hz supply. Find the rms voltage VC across the capacitor.

V = 12 V (rms)f = 100 HzR = 80 ΩL = 20 mHC = 4.7 µF
VC = V
6.Hard
100 V60 HzR = 50 ΩL = 200 mHC = 47 µF

A series RLC circuit is connected to a 100 V (rms), 60 Hz supply. Find the resonant frequency f0 of the circuit.

V = 100 V (rms)f = 60 HzR = 50 ΩL = 200 mHC = 47 µF
f0 = Hz

Answer key

  1. 1. |Z| = 81.05 Ω
  2. 2. I = 4.493 A
  3. 3. I = 1.817 A
  4. 4. L = 63.33 mH
  5. 5. VC = 12.1 V
  6. 6. f0 = 51.91 Hz

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