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
230 V50 HzR = 100 ΩL = 150 mH

A series RL circuit is connected to a 230 V (rms), 50 Hz supply. Find the rms voltage VR across the resistor.

V = 230 V (rms)f = 50 HzR = 100 ΩL = 150 mH
VR = V
2.Easy
230 V50 HzR = 60 ΩL = 100 mHI

A series RL circuit is connected to a 230 V (rms), 50 Hz supply. Find the rms current I.

V = 230 V (rms)f = 50 HzR = 60 ΩL = 100 mH
I = A
3.Medium
120 V50 HzR = 20 ΩL = 100 mHC = 10 µF

A series RLC circuit is connected to a 120 V (rms), 50 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 120 V (rms)f = 50 HzR = 20 ΩL = 100 mHC = 10 µF
φ = °
4.Medium
12 V200 HzR = 50 ΩL = 150 mHC = 2.2 µFI

A series RLC circuit is connected to a 12 V (rms), 200 Hz supply. Find the rms current I.

V = 12 V (rms)f = 200 HzR = 50 ΩL = 150 mHC = 2.2 µF
I = A
5.Hard
24 Vf0​R = 50 ΩL = 100 mHC = 1 µF

A series RLC circuit is driven by a 24 V (rms) source whose frequency is set to the resonant frequency of the circuit. Find the rms voltage VL across the inductor.

V = 24 V (rms)R = 50 ΩL = 100 mHC = 1 µF
VL = V
6.Hard
10 V500 HzR = 60 ΩL = 200 mHC = 10 µF

A series RLC circuit is connected to a 10 V (rms), 500 Hz supply. Find the resonant frequency f0 of the circuit.

V = 10 V (rms)f = 500 HzR = 60 ΩL = 200 mHC = 10 µF
f0 = Hz

Answer key

  1. 1. VR = 208.1 V
  2. 2. I = 3.396 A
  3. 3. φ = −86.01 °
  4. 4. I = 0.06656 A
  5. 5. VL = 151.8 V
  6. 6. f0 = 112.5 Hz

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