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 = 60 ΩL = 50 mH

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

V = 50 V (rms)f = 50 HzR = 60 ΩL = 50 mH
VR = V
2.Easy
12 V60 HzR = 15 ΩL = 100 mH

A series RL circuit is connected to a 12 V (rms), 60 Hz supply. Find the rms voltage VL across the inductor.

V = 12 V (rms)f = 60 HzR = 15 ΩL = 100 mH
VL = V
3.Medium
230 V200 HzR = 15 ΩC = 47 µFI

A resistor and a capacitor are connected in parallel across a 230 V (rms), 200 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 230 V (rms)f = 200 HzR = 15 ΩC = 47 µF
φ = °
4.Medium
230 V1000 HzR = 20 ΩL = 20 mHC = 22 µFI

A series RLC circuit is connected to a 230 V (rms), 1000 Hz supply. Find the rms current I.

V = 230 V (rms)f = 1000 HzR = 20 ΩL = 20 mHC = 22 µF
I = A
5.Hard
100 V60 HzR = 15 ΩL = 50 mHC = 100 µF

A series RLC circuit is connected to a 100 V (rms), 60 Hz supply. Find the resonant frequency f0 of the circuit.

V = 100 V (rms)f = 60 HzR = 15 ΩL = 50 mHC = 100 µF
f0 = Hz
6.Hard
10 V200 HzR = 20 ΩL = 20 mHC = 4.7 µF+−VC​

A series RLC circuit is connected to a 10 V (rms), 200 Hz supply. Find the rms voltage VC across the capacitor.

V = 10 V (rms)f = 200 HzR = 20 ΩL = 20 mHC = 4.7 µF
VC = V

Answer key

  1. 1. VR = 48.37 V
  2. 2. VL = 11.15 V
  3. 3. φ = −41.54 °
  4. 4. I = 1.915 A
  5. 5. f0 = 71.18 Hz
  6. 6. VC = 11.63 V

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