Bode plots & margins worksheet with answers

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

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
vin​R = 10 ΩL = 100 mHvout​

Find the corner (−3 dB) frequency ωc of the RL high-pass filter shown, with R = 10 Ω, L = 100 mH. Give it in rad/s.

R = 10 ΩL = 100 mH
ωc = rad/s
2.Easy
|H| (dB)0.010.11101001000−40−20020406080?ω (rad/s)

Sketch the asymptotic Bode magnitude plot of G(s) = 0.5(s + 100)/(s(s + 0.5)). What is the slope n of the straight-line asymptote below 0.5 rad/s, in dB/decade?

G(s) = 0.5(s + 100)/(s(s + 0.5))
n = dB/dec
3.Medium
vin​C = 2.2 nFR = 3.3 kΩvout​

The RC high-pass filter shown has R = 3.3 kΩ, C = 2.2 nF. A sinusoidal input of 44 kHz is applied. Find the gain |H| = |vout/vin| in dB.

R = 3.3 kΩC = 2.2 nFf = 44 kHz
|H| = dB
4.Medium
vin​C = 100 nFR = 10 kΩvout​

The RC high-pass filter shown has R = 10 kΩ, C = 100 nF. A sinusoidal input of 480 Hz is applied. Find the gain |H| = |vout/vin| in dB.

R = 10 kΩC = 100 nFf = 480 Hz
|H| = dB
5.Hard
|H| (dB)0.10.1111010100100−60−40−2002040ω (rad/s)φ (°)ω (rad/s)−180−135−90−450ωc​

A unity-feedback loop has the open-loop transfer function L(s) = 76/(s(s + 8)). Find the phase margin PM in degrees.

L(s) = 76/(s(s + 8))
PM = °
6.Hard
|H| (dB)0.10.1111010100100−80−60−40−2002040ω (rad/s)φ (°)ω (rad/s)−270−180−900ω180​ = ?

A unity-feedback loop has the open-loop transfer function L(s) = 482/(s(s + 6)(s + 10)). Find the phase crossover frequency ω180, where ∠L(jω) = −180°.

L(s) = 482/(s(s + 6)(s + 10))
ω180 = rad/s

Answer key

  1. 1. ωc = 100 rad/s
  2. 2. n = −20 dB/dec
  3. 3. |H| = −0.963 dB
  4. 4. |H| = −0.453 dB
  5. 5. PM = 48.4 °
  6. 6. ω180 = 7.746 rad/s

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