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
50 V60 HzR = 30 ΩL = 50 mHI

A series RL circuit is connected to a 50 V (rms), 60 Hz supply. Find the rms current I.

V = 50 V (rms)f = 60 HzR = 30 ΩL = 50 mH
I = A
2.Easy
50 V100 HzR = 220 ΩC = 10 µF

A series RC circuit is connected to a 50 V (rms), 100 Hz supply. Find the magnitude of the impedance |Z|.

V = 50 V (rms)f = 100 HzR = 220 ΩC = 10 µF
|Z| = Ω
3.Medium
230 V100 HzR = 60 ΩL = 150 mHI

A resistor and an inductor are connected in parallel across a 230 V (rms), 100 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 230 V (rms)f = 100 HzR = 60 ΩL = 150 mH
φ = °
4.Medium
100 V200 HzR = 60 ΩL = 50 mHC = 2.2 µFI

A series RLC circuit is connected to a 100 V (rms), 200 Hz supply. Find the power factor cos φ of the circuit.

V = 100 V (rms)f = 200 HzR = 60 ΩL = 50 mHC = 2.2 µF
cos φ =
5.Hard
12 V60 HzR = 60 ΩL = 200 mHC = 22 µFI

A series RLC circuit is connected to a 12 V (rms), 60 Hz supply. Find the rms current I.

V = 12 V (rms)f = 60 HzR = 60 ΩL = 200 mHC = 22 µF
I = A
6.Hard
VfR = 1 ΩL = 2 mHC = 0.22 µF

A series RLC circuit has R = 1 Ω, L = 2 mH and C = 0.22 µF. Find its quality factor Q at resonance.

R = 1 ΩL = 2 mHC = 0.22 µF
Q =

Answer key

  1. 1. I = 1.411 A
  2. 2. |Z| = 271.5 Ω
  3. 3. φ = 32.48 °
  4. 4. cos φ = 0.1968
  5. 5. I = 0.1598 A
  6. 6. Q = 95.35

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