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

A series RL circuit is connected to a 24 V (rms), 100 Hz supply. Find the rms voltage V_R across the resistor.

V = 24 V (rms)f = 100 HzR = 40 ΩL = 20 mH

V_R = V

2.Easy

A series RL circuit is connected to a 24 V (rms), 60 Hz supply. Find the rms current I.

V = 24 V (rms)f = 60 HzR = 20 ΩL = 200 mH

I = A

3.Medium

A series RLC circuit is connected to a 120 V (rms), 500 Hz supply. Find the power factor cos φ of the circuit.

V = 120 V (rms)f = 500 HzR = 60 ΩL = 20 mHC = 47 µF

cos φ =

4.Medium

A resistor and a capacitor are connected in parallel across a 12 V (rms), 50 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 12 V (rms)f = 50 HzR = 15 ΩC = 47 µF

φ = °

5.Hard

A resistor R₁ is connected in series with a parallel combination of R₂ and a capacitor C, across a 12 V (rms), 60 Hz supply. Find the rms current I.

V = 12 V (rms)f = 60 HzR₁ = 30 ΩR₂ = 80 ΩC = 47 µF

I = A

6.Hard

A resistor R₁ is connected in series with a parallel combination of R₂ and a capacitor C, across a 100 V (rms), 100 Hz supply. Find the magnitude of the impedance |Z|.

V = 100 V (rms)f = 100 HzR₁ = 20 ΩR₂ = 60 ΩC = 10 µF

|Z| = Ω

Answer key

1. V_R = 22.9 V
2. I = 0.3077 A
3. cos φ = 0.7307
4. φ = −12.49 °
5. I = 0.1765 A
6. |Z| = 75.19 Ω

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