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 V500 HzR = 150 ΩC = 4.7 µF

A series RC 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 = 150 ΩC = 4.7 µF
φ = °
2.Easy
Vf = ?L = 50 mH

At what frequency f does a 50 mH inductor have a reactance of 100 Ω?

L = 50 mHXL = 100 Ω
f = Hz
3.Medium
Vf0​ = 500 HzRL = ?C = 10 µF

A series RLC circuit with C = 10 µF must resonate at 500 Hz. Find the inductance L needed.

f0 = 500 HzC = 10 µF
L = mH
4.Medium
10 V500 HzR = 20 ΩL = 50 mHC = 22 µF

A series RLC circuit is connected to a 10 V (rms), 500 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 10 V (rms)f = 500 HzR = 20 ΩL = 50 mHC = 22 µF
φ = °
5.Hard
24 Vf0​R = 15 ΩL = 200 mHC = 4.7 µF

A series RLC circuit is driven by a 24 V (rms) source whose frequency is set to the resonant frequency of the circuit. Find the rms voltage VL across the inductor.

V = 24 V (rms)R = 15 ΩL = 200 mHC = 4.7 µF
VL = V
6.Hard
50 V100 HzR1​ = 40 ΩR2​ = 20 ΩC = 100 µFI

A resistor R1 is connected in series with a parallel combination of R2 and a capacitor C, across a 50 V (rms), 100 Hz supply. Find the rms current I.

V = 50 V (rms)f = 100 HzR1 = 40 ΩR2 = 20 ΩC = 100 µF
I = A

Answer key

  1. 1. φ = −24.3 °
  2. 2. f = 318.3 Hz
  3. 3. L = 10.13 mH
  4. 4. φ = 82.02 °
  5. 5. VL = 330.1 V
  6. 6. I = 1.026 A

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