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 V50 HzR = 25 ΩL = 100 mH

A series RL circuit is connected to a 12 V (rms), 50 Hz supply. Find the rms voltage VR across the resistor.

V = 12 V (rms)f = 50 HzR = 25 ΩL = 100 mH
VR = V
2.Easy
50 V500 HzR = 150 ΩC = 4.7 µF

A series RC circuit is connected to a 50 V (rms), 500 Hz supply. Find the magnitude of the impedance |Z|.

V = 50 V (rms)f = 500 HzR = 150 ΩC = 4.7 µF
|Z| = Ω
3.Medium
Vf0​ = 1000 HzRL = ?C = 4.7 µF

A series RLC circuit with C = 4.7 µF must resonate at 1000 Hz. Find the inductance L needed.

f0 = 1000 HzC = 4.7 µF
L = mH
4.Medium
230 V200 HzR = 15 ΩL = 200 mHC = 100 µF

A series RLC circuit is connected to a 230 V (rms), 200 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 230 V (rms)f = 200 HzR = 15 ΩL = 200 mHC = 100 µF
φ = °
5.Hard
120 V60 HzR = 60 ΩL = 150 mHC = 4.7 µFI

A series RLC circuit is connected to a 120 V (rms), 60 Hz supply. Find the rms current I.

V = 120 V (rms)f = 60 HzR = 60 ΩL = 150 mHC = 4.7 µF
I = A
6.Hard
120 V60 HzR = 30 ΩL = 50 mHC = 10 µF

A series RLC circuit is connected to a 120 V (rms), 60 Hz supply. Find the resonant frequency f0 of the circuit.

V = 120 V (rms)f = 60 HzR = 30 ΩL = 50 mHC = 10 µF
f0 = Hz

Answer key

  1. 1. VR = 7.472 V
  2. 2. |Z| = 164.6 Ω
  3. 3. L = 5.389 mH
  4. 4. φ = 86.47 °
  5. 5. I = 0.2347 A
  6. 6. f0 = 225.1 Hz

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