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 = 30 ΩL = 200 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 = 30 ΩL = 200 mH
I = A
2.Easy
100 V500 HzR = 30 ΩC = 2.2 µF

A series RC circuit is connected to a 100 V (rms), 500 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 100 V (rms)f = 500 HzR = 30 ΩC = 2.2 µF
φ = °
3.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
4.Medium
50 V60 HzR = 40 ΩL = 50 mHC = 10 µFI

A series RLC circuit is connected to a 50 V (rms), 60 Hz supply. Find the rms current I.

V = 50 V (rms)f = 60 HzR = 40 ΩL = 50 mHC = 10 µF
I = A
5.Hard
12 V200 HzR = 40 ΩL = 20 mHC = 47 µFI

A series RLC circuit is connected to a 12 V (rms), 200 Hz supply. Find the rms current I.

V = 12 V (rms)f = 200 HzR = 40 ΩL = 20 mHC = 47 µF
I = A
6.Hard
230 V50 HzR1​ = 30 ΩR2​ = 80 ΩC = 10 µF

A resistor R1 is connected in series with a parallel combination of R2 and a capacitor C, across a 230 V (rms), 50 Hz supply. Find the magnitude of the impedance |Z|.

V = 230 V (rms)f = 50 HzR1 = 30 ΩR2 = 80 ΩC = 10 µF
|Z| = Ω

Answer key

  1. 1. I = 0.1436 A
  2. 2. φ = −78.29 °
  3. 3. C = 1.267 µF
  4. 4. I = 0.2003 A
  5. 5. I = 0.2939 A
  6. 6. |Z| = 106.9 Ω

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