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 V50 HzR = 30 ΩL = 100 mHI

A series RL circuit is connected to a 24 V (rms), 50 Hz supply. Find the rms current I.

V = 24 V (rms)f = 50 HzR = 30 ΩL = 100 mH
I = A
2.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
3.Medium
100 V100 HzR = 80 ΩL = 150 mHC = 100 µF

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

V = 100 V (rms)f = 100 HzR = 80 ΩL = 150 mHC = 100 µF
φ = °
4.Medium
Vf0​ = 60 HzRL = 100 mHC = ?

A series RLC circuit with L = 100 mH must resonate at 60 Hz. Find the capacitance C needed.

f0 = 60 HzL = 100 mH
C = µF
5.Hard
10 V200 HzR = 80 ΩL = 200 mHC = 47 µF

A series RLC circuit is connected to a 10 V (rms), 200 Hz supply. Find the resonant frequency f0 of the circuit.

V = 10 V (rms)f = 200 HzR = 80 ΩL = 200 mHC = 47 µF
f0 = Hz
6.Hard
5 Vf0​R = 20 ΩL = 50 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 = 20 ΩL = 50 mHC = 10 µF
VL = V

Answer key

  1. 1. I = 0.5525 A
  2. 2. I = 1.343 A
  3. 3. φ = 44.4 °
  4. 4. C = 70.36 µF
  5. 5. f0 = 51.91 Hz
  6. 6. VL = 17.68 V

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