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 V50 HzR = 40 ΩL = 150 mH

A series RL circuit is connected to a 12 V (rms), 50 Hz supply. Find the magnitude of the impedance |Z|.

V = 12 V (rms)f = 50 HzR = 40 ΩL = 150 mH
|Z| = Ω
2.Easy
50 V50 HzR = 10 ΩL = 50 mHI

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

V = 50 V (rms)f = 50 HzR = 10 ΩL = 50 mH
I = A
3.Medium
100 V50 HzR = 15 ΩC = 100 µFI

A resistor and a capacitor are connected in parallel across a 100 V (rms), 50 Hz supply. Find the magnitude of the impedance |Z|.

V = 100 V (rms)f = 50 HzR = 15 ΩC = 100 µF
|Z| = Ω
4.Medium
Vf0​ = 50 HzRL = ?C = 2.2 µF

A series RLC circuit with C = 2.2 µF must resonate at 50 Hz. Find the inductance L needed.

f0 = 50 HzC = 2.2 µF
L = mH
5.Hard
VfR = 10 ΩL = 2 mHC = 0.1 µF

A series RLC circuit has R = 10 Ω, L = 2 mH and C = 0.1 µF. Find its quality factor Q at resonance.

R = 10 ΩL = 2 mHC = 0.1 µF
Q =
6.Hard
VfR = 2 ΩL = 1 mHC = 0.022 µF

A series RLC circuit has R = 2 Ω, L = 1 mH and C = 0.022 µF. Find its quality factor Q at resonance.

R = 2 ΩL = 1 mHC = 0.022 µF
Q =

Answer key

  1. 1. |Z| = 61.81 Ω
  2. 2. I = 2.685 A
  3. 3. |Z| = 13.57 Ω
  4. 4. L = 4606 mH
  5. 5. Q = 14.14
  6. 6. Q = 106.6

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