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 V60 HzR = 60 ΩL = 150 mH

A series RL circuit is connected to a 10 V (rms), 60 Hz supply. Find the rms voltage VL across the inductor.

V = 10 V (rms)f = 60 HzR = 60 ΩL = 150 mH
VL = V
2.Easy
100 V50 HzR = 50 ΩL = 100 mHI

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

V = 100 V (rms)f = 50 HzR = 50 ΩL = 100 mH
I = A
3.Medium
Vf0​ = 1000 HzRL = 5 mHC = ?

A series RLC circuit with L = 5 mH must resonate at 1000 Hz. Find the capacitance C needed.

f0 = 1000 HzL = 5 mH
C = µF
4.Medium
Vf0​ = 100 HzRL = 10 mHC = ?

A series RLC circuit with L = 10 mH must resonate at 100 Hz. Find the capacitance C needed.

f0 = 100 HzL = 10 mH
C = µF
5.Hard
12 V100 HzR = 40 ΩL = 200 mHC = 10 µFI

A series RLC circuit is connected to a 12 V (rms), 100 Hz supply. Find the rms current I.

V = 12 V (rms)f = 100 HzR = 40 ΩL = 200 mHC = 10 µF
I = A
6.Hard
12 V500 HzR = 25 ΩL = 20 mHC = 10 µF

A series RLC circuit is connected to a 12 V (rms), 500 Hz supply. Find the resonant frequency f0 of the circuit.

V = 12 V (rms)f = 500 HzR = 25 ΩL = 20 mHC = 10 µF
f0 = Hz

Answer key

  1. 1. VL = 6.859 V
  2. 2. I = 1.693 A
  3. 3. C = 5.066 µF
  4. 4. C = 253.3 µF
  5. 5. I = 0.23 A
  6. 6. f0 = 355.9 Hz

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