An uncharged capacitor C = 100 µF is charged from a 10 V step source through a resistor R = 2.2 kΩ. How long after closing the switch does the capacitor voltage reach 90 % of its final value? Find t in ms.
Step response worksheet with answers
1.Easy
R = 2.2 kΩC = 100 µFV = 10 V90 %
t = ms
2.Easy
A first-order system G(s) = 40/(s + 20) receives a step input of size 20 at t = 0, starting from rest. Find the final value y(∞) of the output.
G(s) = 40/(s + 20)U = 20
y(∞) =
3.Medium
A system has the transfer function G(s) = 23/(s² + 6s + 23) and receives a unit step input. Find the peak time tp of the step response.
G(s) = 23/(s² + 6s + 23)
tp = s
4.Medium
A system has the transfer function G(s) = 96/(s² + 16s + 96) and receives a unit step input. The poles are s = σ ± jωd. Find the real part σ.
G(s) = 96/(s² + 16s + 96)
σ =
5.Hard
A unity negative feedback loop has G(s) = 30/(s(s + 8)). Find the 2 % settling time ts of the closed-loop step response, using ts ≈ 4/(ζωₙ).
G(s) = 30/(s(s + 8))
ts = s
6.Hard
A unity negative feedback loop has G(s) = K/(s(s + 10)). Find the gain K that gives a step response with 25 % overshoot.
G(s) = K/(s(s + 10))%OS = 25 %
K =
Answer key
- 1. t = 506.6 ms
- 2. y(∞) = 40
- 3. tp = 0.8396 s
- 4. σ = −8
- 5. ts = 1 s
- 6. K = 153.4
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