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 V200 HzR = 60 ΩL = 200 mH

A series RL circuit is connected to a 230 V (rms), 200 Hz supply. Find the rms voltage VL across the inductor.

V = 230 V (rms)f = 200 HzR = 60 ΩL = 200 mH
VL = V
2.Easy
V60 HzL = 50 mH

Find the reactance XL of a 50 mH inductor at 60 Hz.

L = 50 mHf = 60 Hz
XL = Ω
3.Medium
50 V50 HzR = 20 ΩL = 20 mHI

A resistor and an inductor are connected in parallel across a 50 V (rms), 50 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 50 V (rms)f = 50 HzR = 20 ΩL = 20 mH
φ = °
4.Medium
10 V100 HzR = 100 ΩL = 200 mHC = 22 µF

A series RLC circuit is connected to a 10 V (rms), 100 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 10 V (rms)f = 100 HzR = 100 ΩL = 200 mHC = 22 µF
φ = °
5.Hard
12 Vf0​R = 5 ΩL = 20 mHC = 0.47 µF

A series RLC circuit is driven by a 12 V (rms) source whose frequency is set to the resonant frequency of the circuit. Find the rms voltage VL across the inductor.

V = 12 V (rms)R = 5 ΩL = 20 mHC = 0.47 µF
VL = V
6.Hard
100 V50 HzR = 80 ΩL = 20 mHC = 100 µFI

A series RLC circuit is connected to a 100 V (rms), 50 Hz supply. Find the rms current I.

V = 100 V (rms)f = 50 HzR = 80 ΩL = 20 mHC = 100 µF
I = A

Answer key

  1. 1. VL = 223.7 V
  2. 2. XL = 18.85 Ω
  3. 3. φ = 72.56 °
  4. 4. φ = 28.07 °
  5. 5. VL = 495.1 V
  6. 6. I = 1.191 A

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