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
12 V60 HzR = 20 ΩL = 250 mH

A series RL circuit is connected to a 12 V (rms), 60 Hz supply. Find the magnitude of the impedance |Z|.

V = 12 V (rms)f = 60 HzR = 20 ΩL = 250 mH
|Z| = Ω
2.Easy
230 V60 HzR = 40 ΩL = 250 mH

A series RL circuit is connected to a 230 V (rms), 60 Hz supply. Find the magnitude of the impedance |Z|.

V = 230 V (rms)f = 60 HzR = 40 ΩL = 250 mH
|Z| = Ω
3.Medium
Vf0​ = 5000 HzRL = 1 mHC = ?

A series RLC circuit with L = 1 mH must resonate at 5000 Hz. Find the capacitance C needed.

f0 = 5000 HzL = 1 mH
C = µF
4.Medium
100 V500 HzR = 50 ΩL = 250 mHC = 2.2 µFI

A series RLC circuit is connected to a 100 V (rms), 500 Hz supply. Find the rms current I.

V = 100 V (rms)f = 500 HzR = 50 ΩL = 250 mHC = 2.2 µF
I = A
5.Hard
50 V60 HzR1​ = 25 ΩR2​ = 150 ΩC = 4.7 µFI

A resistor R1 is connected in series with a parallel combination of R2 and a capacitor C, across a 50 V (rms), 60 Hz supply. Find the rms current I.

V = 50 V (rms)f = 60 HzR1 = 25 ΩR2 = 150 ΩC = 4.7 µF
I = A
6.Hard
100 V50 HzR = 80 ΩL = 20 mHC = 10 µF

A series RLC circuit is connected to a 100 V (rms), 50 Hz supply. Find the resonant frequency f0 of the circuit.

V = 100 V (rms)f = 50 HzR = 80 ΩL = 20 mHC = 10 µF
f0 = Hz

Answer key

  1. 1. |Z| = 96.35 Ω
  2. 2. |Z| = 102.4 Ω
  3. 3. C = 1.013 µF
  4. 4. I = 0.1556 A
  5. 5. I = 0.2954 A
  6. 6. f0 = 355.9 Hz

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