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
V100 HzC = 47 µF

Find the reactance XC of a 47 µF capacitor at 100 Hz.

C = 47 µFf = 100 Hz
XC = Ω
2.Easy
230 V60 HzR = 100 ΩL = 20 mH

A series RL circuit is connected to a 230 V (rms), 60 Hz supply. Find the magnitude of the impedance |Z|.

V = 230 V (rms)f = 60 HzR = 100 ΩL = 20 mH
|Z| = Ω
3.Medium
120 V500 HzR = 10 ΩL = 50 mHC = 10 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 = 10 ΩL = 50 mHC = 10 µF
I = A
4.Medium
Vf0​ = 5000 HzRL = 10 mHC = ?

A series RLC circuit with L = 10 mH must resonate at 5000 Hz. Find the capacitance C needed.

f0 = 5000 HzL = 10 mH
C = µF
5.Hard
VfR = 100 ΩL = 5 mHC = 0.22 µF

A series RLC circuit has R = 100 Ω, L = 5 mH and C = 0.22 µF. Find its quality factor Q at resonance.

R = 100 ΩL = 5 mHC = 0.22 µF
Q =
6.Hard
VfR = 1 ΩL = 5 mHC = 0.47 µF

A series RLC circuit has R = 1 Ω, L = 5 mH and C = 0.47 µF. Find its bandwidth B (the width of the band between the half-power frequencies), in Hz.

R = 1 ΩL = 5 mHC = 0.47 µF
B = Hz

Answer key

  1. 1. XC = 33.86 Ω
  2. 2. |Z| = 100.3 Ω
  3. 3. I = 0.9551 A
  4. 4. C = 0.1013 µF
  5. 5. Q = 1.508
  6. 6. B = 31.83 Hz

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