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 = 220 ΩC = 22 µFI

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

V = 24 V (rms)f = 50 HzR = 220 ΩC = 22 µF
I = A
2.Easy
Vf = ?L = 50 mH

At what frequency f does a 50 mH inductor have a reactance of 20 Ω?

L = 50 mHXL = 20 Ω
f = Hz
3.Medium
230 V50 HzR = 25 ΩL = 100 mHC = 47 µFI

A series RLC circuit is connected to a 230 V (rms), 50 Hz supply. Find the real power P taken from the supply.

V = 230 V (rms)f = 50 HzR = 25 ΩL = 100 mHC = 47 µF
P = W
4.Medium
Vf0​ = 500 HzRL = ?C = 47 µF

A series RLC circuit with C = 47 µF must resonate at 500 Hz. Find the inductance L needed.

f0 = 500 HzC = 47 µF
L = mH
5.Hard
VfR = 2 ΩL = 2 mHC = 1 µF

A series RLC circuit has R = 2 Ω, L = 2 mH and C = 1 µF. Find its quality factor Q at resonance.

R = 2 ΩL = 2 mHC = 1 µF
Q =
6.Hard
120 V60 HzR = 30 ΩL = 200 mHC = 4.7 µF+−VC​

A series RLC circuit is connected to a 120 V (rms), 60 Hz supply. Find the rms voltage VC across the capacitor.

V = 120 V (rms)f = 60 HzR = 30 ΩL = 200 mHC = 4.7 µF
VC = V

Answer key

  1. 1. I = 0.09115 A
  2. 2. f = 63.66 Hz
  3. 3. P = 680.5 W
  4. 4. L = 2.156 mH
  5. 5. Q = 22.36
  6. 6. VC = 138.2 V

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