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 = 40 ΩL = 200 mH

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

V = 12 V (rms)f = 60 HzR = 40 ΩL = 200 mH
VR = V
2.Easy
230 V60 HzR = 30 ΩL = 100 mHI

A series RL circuit is connected to a 230 V (rms), 60 Hz supply. Find the rms current I.

V = 230 V (rms)f = 60 HzR = 30 ΩL = 100 mH
I = A
3.Medium
120 V50 HzR = 80 ΩL = 150 mHC = 10 µFI

A series RLC circuit is connected to a 120 V (rms), 50 Hz supply. Find the rms current I.

V = 120 V (rms)f = 50 HzR = 80 ΩL = 150 mHC = 10 µF
I = A
4.Medium
120 V500 HzR = 80 ΩC = 4.7 µFI

A resistor and a capacitor are connected in parallel across a 120 V (rms), 500 Hz supply. Find the magnitude of the impedance |Z|.

V = 120 V (rms)f = 500 HzR = 80 ΩC = 4.7 µF
|Z| = Ω
5.Hard
12 V100 HzR = 30 ΩL = 200 mHC = 47 µF+−VC​

A series RLC circuit is connected to a 12 V (rms), 100 Hz supply. Find the rms voltage VC across the capacitor.

V = 12 V (rms)f = 100 HzR = 30 ΩL = 200 mHC = 47 µF
VC = V
6.Hard
VfR = 2 ΩL = 10 mHC = 0.47 µF

A series RLC circuit has R = 2 Ω, L = 10 mH and C = 0.47 µF. Find its quality factor Q at resonance.

R = 2 ΩL = 10 mHC = 0.47 µF
Q =

Answer key

  1. 1. VR = 5.624 V
  2. 2. I = 4.774 A
  3. 3. I = 0.4244 A
  4. 4. |Z| = 51.69 Ω
  5. 5. VC = 4.207 V
  6. 6. Q = 72.93

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