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 = 15 ΩL = 100 mH

A series RL circuit is connected to a 50 V (rms), 50 Hz supply. Find the magnitude of the impedance |Z|.

V = 50 V (rms)f = 50 HzR = 15 ΩL = 100 mH
|Z| = Ω
2.Easy
10 V60 HzR = 25 ΩL = 250 mHI

A series RL circuit is connected to a 10 V (rms), 60 Hz supply. Find the rms current I.

V = 10 V (rms)f = 60 HzR = 25 ΩL = 250 mH
I = A
3.Medium
12 V100 HzR = 80 ΩL = 50 mHC = 4.7 µF

A series RLC circuit is connected to a 12 V (rms), 100 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 12 V (rms)f = 100 HzR = 80 ΩL = 50 mHC = 4.7 µF
φ = °
4.Medium
24 V200 HzR = 25 ΩL = 150 mHC = 10 µFI

A series RLC circuit is connected to a 24 V (rms), 200 Hz supply. Find the real power P taken from the supply.

V = 24 V (rms)f = 200 HzR = 25 ΩL = 150 mHC = 10 µF
P = W
5.Hard
5 Vf0​R = 20 ΩL = 10 mHC = 0.1 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 = 10 mHC = 0.1 µF
VL = V
6.Hard
100 V200 HzR = 50 ΩL = 150 mHC = 22 µFI

A series RLC circuit is connected to a 100 V (rms), 200 Hz supply. Find the rms current I.

V = 100 V (rms)f = 200 HzR = 50 ΩL = 150 mHC = 22 µF
I = A

Answer key

  1. 1. |Z| = 34.81 Ω
  2. 2. I = 0.1026 A
  3. 3. φ = −75.4 °
  4. 4. P = 1.153 W
  5. 5. VL = 79.06 V
  6. 6. I = 0.6238 A

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