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 V50 HzR = 20 ΩL = 100 mHI

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

V = 50 V (rms)f = 50 HzR = 20 ΩL = 100 mH
I = A
2.Easy
230 V50 HzR = 10 ΩL = 20 mH

A series RL circuit is connected to a 230 V (rms), 50 Hz supply. Find the rms voltage VR across the resistor.

V = 230 V (rms)f = 50 HzR = 10 ΩL = 20 mH
VR = V
3.Medium
Vf0​ = 1000 HzRL = ?C = 4.7 µF

A series RLC circuit with C = 4.7 µF must resonate at 1000 Hz. Find the inductance L needed.

f0 = 1000 HzC = 4.7 µF
L = mH
4.Medium
12 V60 HzR = 80 ΩL = 50 mHC = 2.2 µF

A series RLC circuit is connected to a 12 V (rms), 60 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 12 V (rms)f = 60 HzR = 80 ΩL = 50 mHC = 2.2 µF
φ = °
5.Hard
230 V1000 HzR = 10 ΩL = 20 mHC = 22 µF+−VC​

A series RLC circuit is connected to a 230 V (rms), 1000 Hz supply. Find the rms voltage VC across the capacitor.

V = 230 V (rms)f = 1000 HzR = 10 ΩL = 20 mHC = 22 µF
VC = V
6.Hard
10 Vf0​R = 50 ΩL = 50 mHC = 2.2 µF

A series RLC circuit is driven by a 10 V (rms) source whose frequency is set to the resonant frequency of the circuit. Find the rms voltage VL across the inductor.

V = 10 V (rms)R = 50 ΩL = 50 mHC = 2.2 µF
VL = V

Answer key

  1. 1. I = 1.343 A
  2. 2. VR = 194.7 V
  3. 3. L = 5.389 mH
  4. 4. φ = −86.14 °
  5. 5. VC = 14 V
  6. 6. VL = 30.15 V

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