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
Vf = ?L = 500 mH

At what frequency f does a 500 mH inductor have a reactance of 150 Ω?

L = 500 mHXL = 150 Ω
f = Hz
2.Easy
230 V50 HzR = 30 ΩC = 47 µF

A series RC circuit is connected to a 230 V (rms), 50 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 230 V (rms)f = 50 HzR = 30 ΩC = 47 µF
φ = °
3.Medium
Vf0​ = 100 HzRL = 100 mHC = ?

A series RLC circuit with L = 100 mH must resonate at 100 Hz. Find the capacitance C needed.

f0 = 100 HzL = 100 mH
C = µF
4.Medium
50 V60 HzR = 25 ΩL = 200 mHC = 22 µFI

A series RLC circuit is connected to a 50 V (rms), 60 Hz supply. Find the power factor cos φ of the circuit.

V = 50 V (rms)f = 60 HzR = 25 ΩL = 200 mHC = 22 µF
cos φ =
5.Hard
50 V60 HzR = 80 ΩL = 100 mHC = 47 µF

A series RLC circuit is connected to a 50 V (rms), 60 Hz supply. Find the resonant frequency f0 of the circuit.

V = 50 V (rms)f = 60 HzR = 80 ΩL = 100 mHC = 47 µF
f0 = Hz
6.Hard
24 V60 HzR = 30 ΩL = 200 mHC = 47 µF

A series RLC circuit is connected to a 24 V (rms), 60 Hz supply. Find the resonant frequency f0 of the circuit.

V = 24 V (rms)f = 60 HzR = 30 ΩL = 200 mHC = 47 µF
f0 = Hz

Answer key

  1. 1. f = 47.75 Hz
  2. 2. φ = −66.11 °
  3. 3. C = 25.33 µF
  4. 4. cos φ = 0.4842
  5. 5. f0 = 73.41 Hz
  6. 6. f0 = 51.91 Hz

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