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
V400 HzL = 5 mH

Find the reactance XL of a 5 mH inductor at 400 Hz.

L = 5 mHf = 400 Hz
XL = Ω
2.Easy
100 V1000 HzR = 20 ΩC = 100 µFI

A series RC circuit is connected to a 100 V (rms), 1000 Hz supply. Find the rms current I.

V = 100 V (rms)f = 1000 HzR = 20 ΩC = 100 µF
I = A
3.Medium
12 V50 HzR = 100 ΩL = 150 mHC = 10 µF

A series RLC circuit is connected to a 12 V (rms), 50 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 12 V (rms)f = 50 HzR = 100 ΩL = 150 mHC = 10 µF
φ = °
4.Medium
120 V200 HzR = 30 ΩL = 50 mHC = 47 µFI

A series RLC circuit is connected to a 120 V (rms), 200 Hz supply. Find the power factor cos φ of the circuit.

V = 120 V (rms)f = 200 HzR = 30 ΩL = 50 mHC = 47 µF
cos φ =
5.Hard
120 V50 HzR1​ = 15 ΩR2​ = 50 ΩC = 22 µFI

A resistor R1 is connected in series with a parallel combination of R2 and a capacitor C, across a 120 V (rms), 50 Hz supply. Find the rms current I.

V = 120 V (rms)f = 50 HzR1 = 15 ΩR2 = 50 ΩC = 22 µF
I = A
6.Hard
24 V50 HzR = 30 ΩL = 150 mHC = 100 µFI

A series RLC circuit is connected to a 24 V (rms), 50 Hz supply. Find the rms current I.

V = 24 V (rms)f = 50 HzR = 30 ΩL = 150 mHC = 100 µF
I = A

Answer key

  1. 1. XL = 12.57 Ω
  2. 2. I = 4.984 A
  3. 3. φ = −69.76 °
  4. 4. cos φ = 0.5471
  5. 5. I = 1.947 A
  6. 6. I = 0.7127 A

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