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 50 V (rms), 60 Hz supply. Find the rms current I.

V = 50 V (rms)f = 60 HzR = 20 ΩL = 100 mH

I = A

2.Easy

A series RL circuit is connected to a 12 V (rms), 50 Hz supply. Find the magnitude of the impedance |Z|.

V = 12 V (rms)f = 50 HzR = 100 ΩL = 100 mH

|Z| = Ω

3.Medium

A resistor and an inductor are connected in parallel across a 50 V (rms), 500 Hz supply. Find the magnitude of the impedance |Z|.

V = 50 V (rms)f = 500 HzR = 15 ΩL = 20 mH

|Z| = Ω

4.Medium

A series RLC circuit is connected to a 100 V (rms), 200 Hz supply. Find the phase angle φ of the impedance, in degrees (positive when the current lags the voltage).

V = 100 V (rms)f = 200 HzR = 25 ΩL = 50 mHC = 4.7 µF

φ = °

5.Hard

A series RLC circuit is driven by a 10 V (rms) source whose frequency is set to the resonant frequency of the circuit. Find the rms voltage V_L across the inductor.

V = 10 V (rms)R = 15 ΩL = 100 mHC = 10 µF

V_L = V

6.Hard

A resistor R₁ is connected in series with a parallel combination of R₂ and a capacitor C, across a 50 V (rms), 60 Hz supply. Find the magnitude of the impedance |Z|.

V = 50 V (rms)f = 60 HzR₁ = 25 ΩR₂ = 150 ΩC = 47 µF

|Z| = Ω

Answer key

1. I = 1.172 A
2. |Z| = 104.8 Ω
3. |Z| = 14.59 Ω
4. φ = −76.79 °
5. V_L = 66.67 V
6. |Z| = 65.92 Ω

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