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 230 V (rms), 60 Hz supply. Find the magnitude of the impedance |Z|.

V = 230 V (rms)f = 60 HzR = 100 ΩL = 150 mH

|Z| = Ω

2.Easy

A series RL circuit is connected to a 230 V (rms), 100 Hz supply. Find the rms voltage V_R across the resistor.

V = 230 V (rms)f = 100 HzR = 60 ΩL = 20 mH

V_R = V

3.Medium

A series RLC circuit is connected to a 12 V (rms), 60 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 12 V (rms)f = 60 HzR = 60 ΩL = 150 mHC = 100 µF

φ = °

4.Medium

A series RLC circuit is connected to a 230 V (rms), 200 Hz supply. Find the power factor cos φ of the circuit.

V = 230 V (rms)f = 200 HzR = 15 ΩL = 250 mHC = 4.7 µF

cos φ =

5.Hard

A resistor R₁ is connected in series with a parallel combination of R₂ and a capacitor C, across a 24 V (rms), 60 Hz supply. Find the magnitude of the impedance |Z|.

V = 24 V (rms)f = 60 HzR₁ = 20 ΩR₂ = 40 ΩC = 100 µF

|Z| = Ω

6.Hard

A series RLC circuit is driven by a 1 V (rms) source whose frequency is set to the resonant frequency of the circuit. Find the rms voltage V_L across the inductor.

V = 1 V (rms)R = 20 ΩL = 10 mHC = 1 µF

V_L = V

Answer key

1. |Z| = 114.9 Ω
2. V_R = 225.1 V
3. φ = 26.58 °
4. cos φ = 0.103
5. |Z| = 37.11 Ω
6. V_L = 5 V

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