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
50 V50 HzR = 30 ΩL = 100 mHI

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

V = 50 V (rms)f = 50 HzR = 30 ΩL = 100 mH
I = A
2.Easy
100 V50 HzR = 50 ΩL = 150 mH

A series RL circuit is connected to a 100 V (rms), 50 Hz supply. Find the magnitude of the impedance |Z|.

V = 100 V (rms)f = 50 HzR = 50 ΩL = 150 mH
|Z| = Ω
3.Medium
230 V100 HzR = 50 ΩL = 20 mHC = 10 µFI

A series RLC circuit is connected to a 230 V (rms), 100 Hz supply. Find the power factor cos φ of the circuit.

V = 230 V (rms)f = 100 HzR = 50 ΩL = 20 mHC = 10 µF
cos φ =
4.Medium
50 V200 HzR = 25 ΩC = 22 µFI

A resistor and a capacitor are connected in parallel across a 50 V (rms), 200 Hz supply. Find the magnitude of the impedance |Z|.

V = 50 V (rms)f = 200 HzR = 25 ΩC = 22 µF
|Z| = Ω
5.Hard
12 V200 HzR = 50 ΩL = 100 mHC = 10 µF

A series RLC circuit is connected to a 12 V (rms), 200 Hz supply. Find the resonant frequency f0 of the circuit.

V = 12 V (rms)f = 200 HzR = 50 ΩL = 100 mHC = 10 µF
f0 = Hz
6.Hard
12 V50 HzR = 50 ΩL = 250 mHC = 4.7 µF+−VC​

A series RLC circuit is connected to a 12 V (rms), 50 Hz supply. Find the rms voltage VC across the capacitor.

V = 12 V (rms)f = 50 HzR = 50 ΩL = 250 mHC = 4.7 µF
VC = V

Answer key

  1. 1. I = 1.151 A
  2. 2. |Z| = 68.71 Ω
  3. 3. cos φ = 0.3228
  4. 4. |Z| = 20.57 Ω
  5. 5. f0 = 159.2 Hz
  6. 6. VC = 13.53 V

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