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
V200 HzC = 100 µF

Find the reactance XC of a 100 µF capacitor at 200 Hz.

C = 100 µFf = 200 Hz
XC = Ω
2.Easy
12 V60 HzR = 25 ΩL = 200 mHI

A series RL circuit is connected to a 12 V (rms), 60 Hz supply. Find the rms current I.

V = 12 V (rms)f = 60 HzR = 25 ΩL = 200 mH
I = A
3.Medium
Vf0​ = 1000 HzRL = 1 mHC = ?

A series RLC circuit with L = 1 mH must resonate at 1000 Hz. Find the capacitance C needed.

f0 = 1000 HzL = 1 mH
C = µF
4.Medium
230 V200 HzR = 25 ΩL = 20 mHI

A resistor and an inductor are connected in parallel across a 230 V (rms), 200 Hz supply. Find the rms current I.

V = 230 V (rms)f = 200 HzR = 25 ΩL = 20 mH
I = A
5.Hard
10 V60 HzR = 40 ΩL = 20 mHC = 22 µF

A series RLC circuit is connected to a 10 V (rms), 60 Hz supply. Find the resonant frequency f0 of the circuit.

V = 10 V (rms)f = 60 HzR = 40 ΩL = 20 mHC = 22 µF
f0 = Hz
6.Hard
2 Vf0​R = 10 ΩL = 5 mHC = 0.1 µF

A series RLC circuit is driven by a 2 V (rms) source whose frequency is set to the resonant frequency of the circuit. Find the rms voltage VL across the inductor.

V = 2 V (rms)R = 10 ΩL = 5 mHC = 0.1 µF
VL = V

Answer key

  1. 1. XC = 7.958 Ω
  2. 2. I = 0.1511 A
  3. 3. C = 25.33 µF
  4. 4. I = 12.98 A
  5. 5. f0 = 239.9 Hz
  6. 6. VL = 44.72 V

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