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
50 V100 HzR = 30 ΩL = 50 mH

A series RL circuit is connected to a 50 V (rms), 100 Hz supply. Find the rms voltage VR across the resistor.

V = 50 V (rms)f = 100 HzR = 30 ΩL = 50 mH
VR = V
2.Easy
230 V1000 HzR = 10 ΩC = 22 µF

A series RC circuit is connected to a 230 V (rms), 1000 Hz supply. Find the magnitude of the impedance |Z|.

V = 230 V (rms)f = 1000 HzR = 10 ΩC = 22 µF
|Z| = Ω
3.Medium
100 V200 HzR = 15 ΩL = 100 mHC = 47 µF

A series RLC circuit is connected to a 100 V (rms), 200 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 100 V (rms)f = 200 HzR = 15 ΩL = 100 mHC = 47 µF
φ = °
4.Medium
Vf0​ = 2000 HzRL = 100 mHC = ?

A series RLC circuit with L = 100 mH must resonate at 2000 Hz. Find the capacitance C needed.

f0 = 2000 HzL = 100 mH
C = µF
5.Hard
230 V60 HzR1​ = 15 ΩR2​ = 30 ΩC = 100 µFI

A resistor R1 is connected in series with a parallel combination of R2 and a capacitor C, across a 230 V (rms), 60 Hz supply. Find the rms current I.

V = 230 V (rms)f = 60 HzR1 = 15 ΩR2 = 30 ΩC = 100 µF
I = A
6.Hard
230 V50 HzR = 60 ΩL = 50 mHC = 4.7 µF

A series RLC circuit is connected to a 230 V (rms), 50 Hz supply. Find the resonant frequency f0 of the circuit.

V = 230 V (rms)f = 50 HzR = 60 ΩL = 50 mHC = 4.7 µF
f0 = Hz

Answer key

  1. 1. VR = 34.53 V
  2. 2. |Z| = 12.34 Ω
  3. 3. φ = 82.15 °
  4. 4. C = 0.06333 µF
  5. 5. I = 7.22 A
  6. 6. f0 = 328.3 Hz

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