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
24 V200 HzR = 30 ΩC = 47 µF

A series RC circuit is connected to a 24 V (rms), 200 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 24 V (rms)f = 200 HzR = 30 ΩC = 47 µF
φ = °
2.Easy
230 V50 HzR = 60 ΩL = 20 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 = 60 ΩL = 20 mH
I = A
3.Medium
50 V100 HzR = 50 ΩL = 100 mHC = 2.2 µFI

A series RLC circuit is connected to a 50 V (rms), 100 Hz supply. Find the rms current I.

V = 50 V (rms)f = 100 HzR = 50 ΩL = 100 mHC = 2.2 µF
I = A
4.Medium
Vf0​ = 60 HzRL = ?C = 22 µF

A series RLC circuit with C = 22 µF must resonate at 60 Hz. Find the inductance L needed.

f0 = 60 HzC = 22 µF
L = mH
5.Hard
230 V60 HzR = 80 ΩL = 200 mHC = 2.2 µF

A series RLC circuit is connected to a 230 V (rms), 60 Hz supply. Find the resonant frequency f0 of the circuit.

V = 230 V (rms)f = 60 HzR = 80 ΩL = 200 mHC = 2.2 µF
f0 = Hz
6.Hard
1 Vf0​R = 20 ΩL = 50 mHC = 1 µF

A series RLC circuit is driven by a 1 V (rms) source whose frequency is set to the resonant frequency of the circuit. Find the rms voltage VL across the inductor.

V = 1 V (rms)R = 20 ΩL = 50 mHC = 1 µF
VL = V

Answer key

  1. 1. φ = −29.44 °
  2. 2. I = 3.812 A
  3. 3. I = 0.07547 A
  4. 4. L = 319.8 mH
  5. 5. f0 = 239.9 Hz
  6. 6. VL = 11.18 V

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