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
230 V50 HzR = 10 ΩL = 200 mHI

A series RL circuit is connected to a 230 V (rms), 50 Hz supply. Find the rms current I.

V = 230 V (rms)f = 50 HzR = 10 ΩL = 200 mH
I = A
2.Easy
230 V200 HzR = 100 ΩL = 20 mH

A series RL circuit is connected to a 230 V (rms), 200 Hz supply. Find the rms voltage VR across the resistor.

V = 230 V (rms)f = 200 HzR = 100 ΩL = 20 mH
VR = V
3.Medium
Vf0​ = 2000 HzRL = 2 mHC = ?

A series RLC circuit with L = 2 mH must resonate at 2000 Hz. Find the capacitance C needed.

f0 = 2000 HzL = 2 mH
C = µF
4.Medium
100 V500 HzR = 40 ΩL = 150 mHC = 1 µF

A series RLC circuit is connected to a 100 V (rms), 500 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 100 V (rms)f = 500 HzR = 40 ΩL = 150 mHC = 1 µF
φ = °
5.Hard
12 Vf0​R = 15 ΩL = 50 mHC = 2.2 µF

A series RLC circuit is driven by a 12 V (rms) source whose frequency is set to the resonant frequency of the circuit. Find the rms voltage VL across the inductor.

V = 12 V (rms)R = 15 ΩL = 50 mHC = 2.2 µF
VL = V
6.Hard
5 Vf0​R = 5 ΩL = 5 mHC = 10 µF

A series RLC circuit is driven by a 5 V (rms) source whose frequency is set to the resonant frequency of the circuit. Find the rms voltage VL across the inductor.

V = 5 V (rms)R = 5 ΩL = 5 mHC = 10 µF
VL = V

Answer key

  1. 1. I = 3.615 A
  2. 2. VR = 223.1 V
  3. 3. C = 3.166 µF
  4. 4. φ = 75.34 °
  5. 5. VL = 120.6 V
  6. 6. VL = 22.36 V

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