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.

New worksheetPractise online with hints

For teachers: free to print, copy and use in class. Every new worksheet has new values and its own answer key. A link to ExamProblems on your course page is appreciated.

Name: ____________________   Date: ____________

1.Easy
230 V50 HzR = 10 ΩL = 20 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 = 10 ΩL = 20 mH
VL = V
2.Easy
10 V50 HzR = 30 ΩL = 20 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 = 30 ΩL = 20 mH
|Z| = Ω
3.Medium
12 V500 HzR = 80 ΩL = 50 mHI

A resistor and an inductor are connected in parallel across a 12 V (rms), 500 Hz supply. Find the rms current I.

V = 12 V (rms)f = 500 HzR = 80 ΩL = 50 mH
I = A
4.Medium
100 V200 HzR = 25 ΩL = 150 mHC = 10 µFI

A series RLC circuit is connected to a 100 V (rms), 200 Hz supply. Find the power factor cos φ of the circuit.

V = 100 V (rms)f = 200 HzR = 25 ΩL = 150 mHC = 10 µF
cos φ =
5.Hard
2 Vf0​R = 50 ΩL = 20 mHC = 0.1 µF

A series RLC circuit is driven by a 2 V (rms) source whose frequency is set to the resonant frequency of the circuit. Find the rms voltage VL across the inductor.

V = 2 V (rms)R = 50 ΩL = 20 mHC = 0.1 µF
VL = V
6.Hard
10 V50 HzR = 10 ΩL = 50 mHC = 100 µF

A series RLC circuit is connected to a 10 V (rms), 50 Hz supply. Find the resonant frequency f0 of the circuit.

V = 10 V (rms)f = 50 HzR = 10 ΩL = 50 mHC = 100 µF
f0 = Hz

Answer key

  1. 1. VL = 122.4 V
  2. 2. |Z| = 30.65 Ω
  3. 3. I = 0.1683 A
  4. 4. cos φ = 0.2237
  5. 5. VL = 17.89 V
  6. 6. f0 = 71.18 Hz

Full step-by-step solutions: practise this topic on examproblems.com.