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
12 V60 HzR = 15 ΩC = 10 µF

A series RC circuit is connected to a 12 V (rms), 60 Hz supply. Find the magnitude of the impedance |Z|.

V = 12 V (rms)f = 60 HzR = 15 ΩC = 10 µF
|Z| = Ω
2.Easy
10 V60 HzR = 220 ΩC = 100 µF

A series RC circuit is connected to a 10 V (rms), 60 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 10 V (rms)f = 60 HzR = 220 ΩC = 100 µF
φ = °
3.Medium
12 V500 HzR = 40 ΩL = 200 mHC = 100 µF

A series RLC circuit is connected to a 12 V (rms), 500 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 12 V (rms)f = 500 HzR = 40 ΩL = 200 mHC = 100 µF
φ = °
4.Medium
Vf0​ = 1000 HzRL = ?C = 0.22 µF

A series RLC circuit with C = 0.22 µF must resonate at 1000 Hz. Find the inductance L needed.

f0 = 1000 HzC = 0.22 µF
L = mH
5.Hard
50 V50 HzR = 80 ΩL = 20 mHC = 100 µFI

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

V = 50 V (rms)f = 50 HzR = 80 ΩL = 20 mHC = 100 µF
I = A
6.Hard
5 Vf0​R = 5 ΩL = 10 mHC = 0.22 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 = 5 ΩL = 10 mHC = 0.22 µF
VL = V

Answer key

  1. 1. |Z| = 265.7 Ω
  2. 2. φ = −6.875 °
  3. 3. φ = 86.34 °
  4. 4. L = 115.1 mH
  5. 5. I = 0.5954 A
  6. 6. VL = 213.2 V

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