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 V60 HzR = 40 ΩL = 150 mHI

A series RL circuit is connected to a 10 V (rms), 60 Hz supply. Find the rms current I.

V = 10 V (rms)f = 60 HzR = 40 ΩL = 150 mH
I = A
2.Easy
V50 HzC = 1 µF

Find the reactance XC of a 1 µF capacitor at 50 Hz.

C = 1 µFf = 50 Hz
XC = Ω
3.Medium
120 V100 HzR = 60 ΩL = 150 mHC = 2.2 µF

A series RLC circuit is connected to a 120 V (rms), 100 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 120 V (rms)f = 100 HzR = 60 ΩL = 150 mHC = 2.2 µF
φ = °
4.Medium
Vf0​ = 1000 HzRL = 20 mHC = ?

A series RLC circuit with L = 20 mH must resonate at 1000 Hz. Find the capacitance C needed.

f0 = 1000 HzL = 20 mH
C = µF
5.Hard
24 V200 HzR1​ = 25 ΩR2​ = 30 ΩC = 47 µFI

A resistor R1 is connected in series with a parallel combination of R2 and a capacitor C, across a 24 V (rms), 200 Hz supply. Find the rms current I.

V = 24 V (rms)f = 200 HzR1 = 25 ΩR2 = 30 ΩC = 47 µF
I = A
6.Hard
120 V500 HzR1​ = 10 ΩR2​ = 50 ΩC = 10 µFI

A resistor R1 is connected in series with a parallel combination of R2 and a capacitor C, across a 120 V (rms), 500 Hz supply. Find the rms current I.

V = 120 V (rms)f = 500 HzR1 = 10 ΩR2 = 50 ΩC = 10 µF
I = A

Answer key

  1. 1. I = 0.1444 A
  2. 2. XC = 3183 Ω
  3. 3. φ = −84.55 °
  4. 4. C = 1.267 µF
  5. 5. I = 0.6914 A
  6. 6. I = 3.603 A

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