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
10 V50 HzR = 10 ΩL = 150 mH

A series RL circuit is connected to a 10 V (rms), 50 Hz supply. Find the magnitude of the impedance |Z|.

V = 10 V (rms)f = 50 HzR = 10 ΩL = 150 mH
|Z| = Ω
2.Easy
V1000 HzC = 0.1 µF

Find the reactance XC of a 0.1 µF capacitor at 1000 Hz.

C = 0.1 µFf = 1000 Hz
XC = Ω
3.Medium
10 V1000 HzR = 25 ΩL = 50 mHC = 4.7 µF

A series RLC circuit is connected to a 10 V (rms), 1000 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 10 V (rms)f = 1000 HzR = 25 ΩL = 50 mHC = 4.7 µF
φ = °
4.Medium
50 V100 HzR = 50 ΩL = 20 mHC = 4.7 µFI

A series RLC circuit is connected to a 50 V (rms), 100 Hz supply. Find the power factor cos φ of the circuit.

V = 50 V (rms)f = 100 HzR = 50 ΩL = 20 mHC = 4.7 µF
cos φ =
5.Hard
100 V1000 HzR = 100 ΩL = 200 mHC = 100 µFI

A series RLC circuit is connected to a 100 V (rms), 1000 Hz supply. Find the rms current I.

V = 100 V (rms)f = 1000 HzR = 100 ΩL = 200 mHC = 100 µF
I = A
6.Hard
230 V50 HzR = 60 ΩL = 150 mHC = 47 µF

A series RLC circuit is connected to a 230 V (rms), 50 Hz supply. Find the resonant frequency f0 of the circuit.

V = 230 V (rms)f = 50 HzR = 60 ΩL = 150 mHC = 47 µF
f0 = Hz

Answer key

  1. 1. |Z| = 48.17 Ω
  2. 2. XC = 1592 Ω
  3. 3. φ = 84.9 °
  4. 4. cos φ = 0.1516
  5. 5. I = 0.07943 A
  6. 6. f0 = 59.94 Hz

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