RC & RL transients worksheet with answers

Free printable RC & RL transients worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

New worksheetPractise online with hints

For teachers: free to print, copy and use in class. Every new worksheet has new values and its own answer key. A link to ExamProblems on your course page is appreciated.

Name: ____________________   Date: ____________

1.Easy
+−Vs​5 Vt = 0R = 1 kΩC100 µF+−vC​

The capacitor is uncharged when the switch closes at t = 0. Find the capacitor voltage vC at t = 80 ms.

Vs = 5 VR = 1 kΩC = 100 µFt = 80 ms
vC = V
2.Easy
+−Vs​20 Vt = 0R = 1 kΩC33 µF+−vC​i

The capacitor is uncharged when the switch closes at t = 0. Find the current i(0⁺) just after the switch closes.

Vs = 20 VR = 1 kΩC = 33 µF
i(0⁺) = mA
3.Medium
+−Vs​12 Vt = 0R = 20 ΩL47 mHi(t)

The inductor carries no current before the switch closes at t = 0. How long after the switch closes does the current reach 99% of its final value? Find t.

Vs = 12 VR = 20 ΩL = 47 mH
t = ms
4.Medium
+−Vs​15 Vt = 0R = 100 ΩL10 mHi(t)

The inductor carries no current before the switch closes at t = 0. Find the voltage vL across the inductor at t = 1 ms.

Vs = 15 VR = 100 ΩL = 10 mHt = 1 ms
vL = V
5.Hard
+−Vs​10 VR1​ = 15 ΩR2​ = 22 Ωopens at t = 0L33 mHi(t)

The switch across R2 has been closed for a long time, so the inductor current is steady. At t = 0 the switch opens. Find the inductor current i at t = 1 ms.

Vs = 10 VR1 = 15 ΩR2 = 22 ΩL = 33 mHt = 1 ms
i = A
6.Hard
+−Vs​12 Vt = 0R = 4.7 kΩC33 µF+−vC​vC​(0) = 10 V

Just before the switch closes at t = 0, the capacitor holds 10 V with the polarity shown. Find the capacitor voltage vC at t = 60 ms.

Vs = 12 VR = 4.7 kΩC = 33 µFvC(0) = 10 Vt = 60 ms
vC = V

Answer key

  1. 1. vC = 2.753 V
  2. 2. i(0⁺) = 20 mA
  3. 3. t = 10.82 ms
  4. 4. vL = 0.000681 V
  5. 5. i = 0.3994 A
  6. 6. vC = 10.64 V

Full step-by-step solutions: practise this topic on examproblems.com.