A step is applied to a first-order process at t = 0. The output starts at 0 and settles at 5. At t = 10 s it reads 2. Find the time constant τ.
Step response worksheet with answers
A first-order system G(s) = 2.5/(s + 0.5) receives a step input of size 5 at t = 0, starting from rest. Find the output y(1.4) at t = 1.4 s.
A system has the transfer function G(s) = 61/(s² + 3s + 61) and receives a unit step input. Find the peak time tp of the step response.
A system has the transfer function G(s) = 120/(s² + 7s + 60) and receives a unit step input. The poles are s = σ ± jωd. Find the real part σ.
A series RLC circuit with R = 63 Ω, L = 100 mH and C = 1 µF is connected to a 5 V step at t = 0. The capacitor is uncharged and no current flows before the step. Find the undamped natural frequency ωn in rad/s.
A unity negative feedback loop has G(s) = 150/(s(s + 16)). Find the 2 % settling time ts of the closed-loop step response, using ts ≈ 4/(ζωₙ).
Answer key
- 1. τ = 19.58 s
- 2. y(1.4) = 12.59
- 3. tp = 0.4099 s
- 4. σ = −3.5
- 5. ωn = 3162 rad/s
- 6. ts = 0.5 s
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