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
12 V50 HzR = 25 ΩL = 100 mH

A series RL circuit is connected to a 12 V (rms), 50 Hz supply. Find the rms voltage VL across the inductor.

V = 12 V (rms)f = 50 HzR = 25 ΩL = 100 mH
VL = V
2.Easy
100 V50 HzR = 80 ΩL = 50 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 = 80 ΩL = 50 mH
|Z| = Ω
3.Medium
Vf0​ = 500 HzRL = ?C = 47 µF

A series RLC circuit with C = 47 µF must resonate at 500 Hz. Find the inductance L needed.

f0 = 500 HzC = 47 µF
L = mH
4.Medium
50 V60 HzR = 15 ΩL = 150 mHI

A resistor and an inductor are connected in parallel across a 50 V (rms), 60 Hz supply. Find the rms current I.

V = 50 V (rms)f = 60 HzR = 15 ΩL = 150 mH
I = A
5.Hard
120 V500 HzR = 80 ΩL = 50 mHC = 2.2 µFI

A series RLC circuit is connected to a 120 V (rms), 500 Hz supply. Find the rms current I.

V = 120 V (rms)f = 500 HzR = 80 ΩL = 50 mHC = 2.2 µF
I = A
6.Hard
10 V200 HzR = 100 ΩL = 200 mHC = 10 µFI

A series RLC circuit is connected to a 10 V (rms), 200 Hz supply. Find the rms current I.

V = 10 V (rms)f = 200 HzR = 100 ΩL = 200 mHC = 10 µF
I = A

Answer key

  1. 1. VL = 9.39 V
  2. 2. |Z| = 81.53 Ω
  3. 3. L = 2.156 mH
  4. 4. I = 3.449 A
  5. 5. I = 1.482 A
  6. 6. I = 0.05032 A

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