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
100 V60 HzR = 100 ΩL = 50 mHI

A series RL circuit is connected to a 100 V (rms), 60 Hz supply. Find the rms current I.

V = 100 V (rms)f = 60 HzR = 100 ΩL = 50 mH
I = A
2.Easy
Vf = ?L = 1 mH

At what frequency f does a 1 mH inductor have a reactance of 20 Ω?

L = 1 mHXL = 20 Ω
f = Hz
3.Medium
230 V50 HzR = 40 ΩL = 50 mHC = 22 µF

A series RLC circuit is connected to a 230 V (rms), 50 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 230 V (rms)f = 50 HzR = 40 ΩL = 50 mHC = 22 µF
φ = °
4.Medium
230 V200 HzR = 40 ΩC = 4.7 µFI

A resistor and a capacitor are connected in parallel across a 230 V (rms), 200 Hz supply. Find the magnitude of the impedance |Z|.

V = 230 V (rms)f = 200 HzR = 40 ΩC = 4.7 µF
|Z| = Ω
5.Hard
5 Vf0​R = 20 ΩL = 5 mHC = 4.7 µF

A series RLC circuit is driven by a 5 V (rms) source whose frequency is set to the resonant frequency of the circuit. Find the rms voltage VL across the inductor.

V = 5 V (rms)R = 20 ΩL = 5 mHC = 4.7 µF
VL = V
6.Hard
24 V200 HzR = 15 ΩL = 200 mHC = 4.7 µF

A series RLC circuit is connected to a 24 V (rms), 200 Hz supply. Find the resonant frequency f0 of the circuit.

V = 24 V (rms)f = 200 HzR = 15 ΩL = 200 mHC = 4.7 µF
f0 = Hz

Answer key

  1. 1. I = 0.9827 A
  2. 2. f = 3183 Hz
  3. 3. φ = −72.77 °
  4. 4. |Z| = 38.93 Ω
  5. 5. VL = 8.154 V
  6. 6. f0 = 164.2 Hz

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