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 V50 HzR = 80 ΩL = 20 mHI

A series RL circuit is connected to a 10 V (rms), 50 Hz supply. Find the rms current I.

V = 10 V (rms)f = 50 HzR = 80 ΩL = 20 mH
I = A
2.Easy
120 V100 HzR = 30 ΩL = 150 mH

A series RL circuit is connected to a 120 V (rms), 100 Hz supply. Find the rms voltage VL across the inductor.

V = 120 V (rms)f = 100 HzR = 30 ΩL = 150 mH
VL = V
3.Medium
120 V500 HzR = 40 ΩC = 22 µFI

A resistor and a capacitor are connected in parallel across a 120 V (rms), 500 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 120 V (rms)f = 500 HzR = 40 ΩC = 22 µF
φ = °
4.Medium
Vf0​ = 2000 HzRL = 5 mHC = ?

A series RLC circuit with L = 5 mH must resonate at 2000 Hz. Find the capacitance C needed.

f0 = 2000 HzL = 5 mH
C = µF
5.Hard
24 V500 HzR1​ = 50 ΩR2​ = 40 ΩC = 10 µFI

A resistor R1 is connected in series with a parallel combination of R2 and a capacitor C, across a 24 V (rms), 500 Hz supply. Find the rms current I.

V = 24 V (rms)f = 500 HzR1 = 50 ΩR2 = 40 ΩC = 10 µF
I = A
6.Hard
50 V200 HzR1​ = 40 ΩR2​ = 20 ΩC = 10 µF

A resistor R1 is connected in series with a parallel combination of R2 and a capacitor C, across a 50 V (rms), 200 Hz supply. Find the magnitude of the impedance |Z|.

V = 50 V (rms)f = 200 HzR1 = 40 ΩR2 = 20 ΩC = 10 µF
|Z| = Ω

Answer key

  1. 1. I = 0.1246 A
  2. 2. VL = 114.3 V
  3. 3. φ = −70.11 °
  4. 4. C = 1.267 µF
  5. 5. I = 0.3512 A
  6. 6. |Z| = 59 Ω

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