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 10 V (rms), 50 Hz supply. Find the magnitude of the impedance |Z|.

V = 10 V (rms)f = 50 HzR = 30 ΩL = 250 mH

|Z| = Ω

2.Easy

A series RL circuit is connected to a 120 V (rms), 50 Hz supply. Find the rms current I.

V = 120 V (rms)f = 50 HzR = 15 ΩL = 200 mH

I = A

3.Medium

A series RLC circuit is connected to a 230 V (rms), 500 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 230 V (rms)f = 500 HzR = 50 ΩL = 250 mHC = 100 µF

φ = °

4.Medium

A series RLC circuit is connected to a 24 V (rms), 500 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 24 V (rms)f = 500 HzR = 100 ΩL = 100 mHC = 4.7 µF

φ = °

5.Hard

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

V = 50 V (rms)f = 50 HzR₁ = 30 ΩR₂ = 150 ΩC = 22 µF

|Z| = Ω

6.Hard

A series RLC circuit is driven by a 24 V (rms) source whose frequency is set to the resonant frequency of the circuit. Find the rms voltage V_L across the inductor.

V = 24 V (rms)R = 15 ΩL = 5 mHC = 0.47 µF

V_L = V

Answer key

1. |Z| = 84.07 Ω
2. I = 1.858 A
3. φ = 86.34 °
4. φ = 67.91 °
5. |Z| = 126.8 Ω
6. V_L = 165 V

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