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 = 50 ΩL = 150 mH

A series RL circuit is connected to a 12 V (rms), 60 Hz supply. Find the rms voltage VL across the inductor.

V = 12 V (rms)f = 60 HzR = 50 ΩL = 150 mH
VL = V
2.Easy
24 V200 HzR = 100 ΩC = 100 µF

A series RC circuit is connected to a 24 V (rms), 200 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 24 V (rms)f = 200 HzR = 100 ΩC = 100 µF
φ = °
3.Medium
120 V500 HzR = 30 ΩL = 200 mHC = 4.7 µFI

A series RLC circuit is connected to a 120 V (rms), 500 Hz supply. Find the rms current I.

V = 120 V (rms)f = 500 HzR = 30 ΩL = 200 mHC = 4.7 µF
I = A
4.Medium
120 V200 HzR = 40 ΩL = 50 mHI

A resistor and an inductor are connected in parallel across a 120 V (rms), 200 Hz supply. Find the rms current I.

V = 120 V (rms)f = 200 HzR = 40 ΩL = 50 mH
I = A
5.Hard
100 V200 HzR = 20 ΩL = 50 mHC = 100 µF

A series RLC circuit is connected to a 100 V (rms), 200 Hz supply. Find the resonant frequency f0 of the circuit.

V = 100 V (rms)f = 200 HzR = 20 ΩL = 50 mHC = 100 µF
f0 = Hz
6.Hard
5 Vf0​R = 20 ΩL = 5 mHC = 4.7 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 = 5 mHC = 4.7 µF
VL = V

Answer key

  1. 1. VL = 8.99 V
  2. 2. φ = −4.55 °
  3. 3. I = 0.2138 A
  4. 4. I = 3.556 A
  5. 5. f0 = 71.18 Hz
  6. 6. VL = 8.154 V

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