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 V500 HzR = 220 ΩC = 1 µF

A series RC circuit is connected to a 50 V (rms), 500 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 50 V (rms)f = 500 HzR = 220 ΩC = 1 µF
φ = °
2.Easy
230 V50 HzR = 30 ΩL = 20 mHI

A series RL circuit is connected to a 230 V (rms), 50 Hz supply. Find the rms current I.

V = 230 V (rms)f = 50 HzR = 30 ΩL = 20 mH
I = A
3.Medium
12 V50 HzR = 10 ΩL = 50 mHI

A resistor and an inductor are connected in parallel across a 12 V (rms), 50 Hz supply. Find the rms current I.

V = 12 V (rms)f = 50 HzR = 10 ΩL = 50 mH
I = A
4.Medium
Vf0​ = 2000 HzRL = ?C = 22 µF

A series RLC circuit with C = 22 µF must resonate at 2000 Hz. Find the inductance L needed.

f0 = 2000 HzC = 22 µF
L = mH
5.Hard
10 V60 HzR = 20 ΩL = 20 mHC = 100 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 = 20 ΩL = 20 mHC = 100 µF
f0 = Hz
6.Hard
230 V50 HzR = 20 ΩL = 100 mHC = 10 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 = 20 ΩL = 100 mHC = 10 µF
f0 = Hz

Answer key

  1. 1. φ = −55.35 °
  2. 2. I = 7.504 A
  3. 3. I = 1.423 A
  4. 4. L = 0.2878 mH
  5. 5. f0 = 112.5 Hz
  6. 6. f0 = 159.2 Hz

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