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
24 V60 HzR = 10 ΩL = 200 mH

A series RL circuit is connected to a 24 V (rms), 60 Hz supply. Find the magnitude of the impedance |Z|.

V = 24 V (rms)f = 60 HzR = 10 ΩL = 200 mH
|Z| = Ω
2.Easy
24 V500 HzR = 220 ΩC = 4.7 µF

A series RC circuit is connected to a 24 V (rms), 500 Hz supply. Find the magnitude of the impedance |Z|.

V = 24 V (rms)f = 500 HzR = 220 ΩC = 4.7 µF
|Z| = Ω
3.Medium
Vf0​ = 5000 HzRL = 2 mHC = ?

A series RLC circuit with L = 2 mH must resonate at 5000 Hz. Find the capacitance C needed.

f0 = 5000 HzL = 2 mH
C = µF
4.Medium
24 V100 HzR = 100 ΩL = 150 mHI

A resistor and an inductor are connected in parallel across a 24 V (rms), 100 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 24 V (rms)f = 100 HzR = 100 ΩL = 150 mH
φ = °
5.Hard
12 Vf0​R = 2 ΩL = 20 mHC = 4.7 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 = 2 ΩL = 20 mHC = 4.7 µF
VL = V
6.Hard
VfR = 15 ΩL = 2 mHC = 2.2 µF

A series RLC circuit has R = 15 Ω, L = 2 mH and C = 2.2 µF. Find its quality factor Q at resonance.

R = 15 ΩL = 2 mHC = 2.2 µF
Q =

Answer key

  1. 1. |Z| = 76.06 Ω
  2. 2. |Z| = 230.2 Ω
  3. 3. C = 0.5066 µF
  4. 4. φ = 46.7 °
  5. 5. VL = 391.4 V
  6. 6. Q = 2.01

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