A step is applied to a first-order process at t = 0. The output starts at 0 and settles at 20. At t = 1 s it reads 18. Find the time constant τ.
Step response worksheet with answers
An uncharged capacitor C = 22 µF is charged from a 5 V step source through a resistor R = 100 kΩ. How long after closing the switch does the capacitor voltage reach 50 % of its final value? Find t in ms.
A system has the transfer function G(s) = 17/(s² + 3s + 17) and receives a unit step input. Find the 2 % settling time ts of the step response, using ts ≈ 4/(ζωₙ).
A system has the transfer function G(s) = 40/(s² + 3s + 20) and receives a unit step input. Find the 2 % settling time ts of the step response, using ts ≈ 4/(ζωₙ).
A series RLC circuit with R = 253 Ω, L = 100 mH and C = 1 µF is connected to a 24 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) = K/(s(s + 6)). Find the gain K that gives a step response with 20 % overshoot.
Answer key
- 1. τ = 0.4343 s
- 2. t = 1525 ms
- 3. ts = 2.667 s
- 4. ts = 2.667 s
- 5. ωn = 3162 rad/s
- 6. K = 43.29
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