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 V1000 HzR = 60 ΩC = 47 µF

A series RC circuit is connected to a 50 V (rms), 1000 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 50 V (rms)f = 1000 HzR = 60 ΩC = 47 µF
φ = °
2.Easy
100 V60 HzR = 100 ΩL = 100 mHI

A series RL circuit is connected to a 100 V (rms), 60 Hz supply. Find the rms current I.

V = 100 V (rms)f = 60 HzR = 100 ΩL = 100 mH
I = A
3.Medium
230 V100 HzR = 25 ΩL = 200 mHC = 100 µFI

A series RLC circuit is connected to a 230 V (rms), 100 Hz supply. Find the power factor cos φ of the circuit.

V = 230 V (rms)f = 100 HzR = 25 ΩL = 200 mHC = 100 µF
cos φ =
4.Medium
230 V200 HzR = 20 ΩL = 100 mHC = 10 µFI

A series RLC circuit is connected to a 230 V (rms), 200 Hz supply. Find the real power P taken from the supply.

V = 230 V (rms)f = 200 HzR = 20 ΩL = 100 mHC = 10 µF
P = W
5.Hard
230 V200 HzR = 60 ΩL = 250 mHC = 4.7 µF+−VC​

A series RLC circuit is connected to a 230 V (rms), 200 Hz supply. Find the rms voltage VC across the capacitor.

V = 230 V (rms)f = 200 HzR = 60 ΩL = 250 mHC = 4.7 µF
VC = V
6.Hard
VfR = 100 ΩL = 50 mHC = 1 µF

A series RLC circuit has R = 100 Ω, L = 50 mH and C = 1 µF. Find its bandwidth B (the width of the band between the half-power frequencies), in Hz.

R = 100 ΩL = 50 mHC = 1 µF
B = Hz

Answer key

  1. 1. φ = −3.23 °
  2. 2. I = 0.9357 A
  3. 3. cos φ = 0.2221
  4. 4. P = 419.2 W
  5. 5. VC = 248.4 V
  6. 6. B = 318.3 Hz

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