What is Step response: Definition and 39 Discussions

The step response of a system in a given initial state consists of the time evolution of its outputs when its control inputs are Heaviside step functions. In electronic engineering and control theory, step response is the time behaviour of the outputs of a general system when its inputs change from zero to one in a very short time. The concept can be extended to the abstract mathematical notion of a dynamical system using an evolution parameter.
From a practical standpoint, knowing how the system responds to a sudden input is important because large and possibly fast deviations from the long term steady state may have extreme effects on the component itself and on other portions of the overall system dependent on this component. In addition, the overall system cannot act until the component's output settles down to some vicinity of its final state, delaying the overall system response. Formally, knowing the step response of a dynamical system gives information on the stability of such a system, and on its ability to reach one stationary state when starting from another.

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  1. johnsmith7565

    Engineering First Order RL Circuit: Finding a Current I2(0-)

    I shorted the inductor and performed mesh analysis. The solutions to the linear system were done using a calculator. The book says that the value for i2(0-) should be 15 mA but I'm getting -2mA. What am I doing wrong? I'm completely confused. Maybe mesh isn't the most efficient way to find I2...
  2. X

    Engineering Step response of RC circuit with independent voltage and current sources

    Dear PF, In the figure down below is Q7.47 which asks to determine the voltage v(t) across the capacitor for t > 0. Since it is given that V(0) = 0 there are two scenario's which is between time interval 0 < t < 1 and t > 1 according to the independent sources. For the scenario 0 < t < 1 the...
  3. halleff

    Physical/conceptual reason for inductor voltage step response

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  4. dRic2

    MATLAB Ltiview and negative step response of a linear system

    Hi, my professor gave me I code where he used to evaluate the answer of a linear system to a step increase in the input variables like this: MySystem = ss(A, B, C, D); ltiveiw('step', MySystem, 'r-', 300); My problem is that with this code I get the response only for a positive step. I'd...
  5. F

    Step Response Characteristics in Simulink

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  6. J

    Impulse reponse from step response

    Homework Statement Homework Equations Derivative of step response is impulse response The Attempt at a Solution [/B] I marked A cause it matches the other coefficients. But where does 9 come from in the last term. I tried with laplace and got the last term as 9. But how to get that in time...
  7. J

    Step Response from the Impulse Response

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  8. M

    Calculating the time taken for the step response of a system

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  9. thegreengineer

    Understanding Root Locus Method: Stability and Response of Control Systems

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  10. whatphysics

    Need help in step response circuit diagram

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  11. I

    Impulse and step response related to the angular position of a spacecraft

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  12. A

    Matlab step response. Just need a quick check

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  13. Domenico94

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  14. T

    Use convolution integral to find step response of a system

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  15. K

    What happens when a battery is connected to an ideal LC circuit?

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  16. K

    Step response time of control system

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  17. 2

    Why does this step response overshoot?

    I have this transfer function which i don't know why it is overshooting due to an step input. http://snag.gy/Vh1SM.jpg Could someone explain why it does that. It's it a close loop transfer function, where I've designed a controller for it, but for some reason, eventhoug all my poles...
  18. C

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    I think I mostly understand how this works, and it makes intuitive sense. However, I'm a little bit confused by one step in the proving of this. On the second page of the attached PDF, there is this statement: x' + kx = (r/k + c2)δ(t) ... (followed by the cases of t<0 and t>0 What comes...
  19. V

    Engineering Finding the step response of RL circuit

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  20. A

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  21. P

    Natural and step response RLC find iL(t)

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  22. M

    Engineering Laplace Step Response Circuit Analysis

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  23. O

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  24. E

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  25. E

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  26. M

    Finding Tau and K from unit step response

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  27. C

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  28. A

    Unit step response and unit impulse response

    In my ODE course I learned that for a time invariant operator p(D), if p(D)x=q(t) then p(D)\dot{x}=\dot{q}(t). Then the professor "justified" that the derivative of the unit step response, v(t), is the unit impulse response, w(t), because the derivative of unit step function is the Dirac...
  29. H

    Voltage step response of impedance frequency response

    Hi I am a bit unsure about terminology and method, so I would like to discuss this with anyone who knows anything about this. I'm examining the properties of a network of parallel capacitors. I have calculated an impedance versus frequency curve, Z(f), using complex impedance of the...
  30. D

    Step response of a RC circuit asking for i(t)

    Homework Statement In attachment Homework Equations i don't understand why it would be asking for the current going through the capcitor, in a dc circuit it should be an open circuit but there will be a voltage over it... after searching through lecture notes and textbook can't find...
  31. M

    Step response and peak response of a transfer function

    Homework Statement The open loop transfer function to a unity negative feedback system is given as: G(s)=50/s(s+10) Homework Equations Unity feedback is used in this problem, and the system input is a step function. Y(s)=50/s(s^2+10s+50) The Attempt at a Solution I have...
  32. S

    Engineering Help with Step Response of an RC circuit

    Homework Statement Derive the Voltage and Current equations for Step Response of an RC circuit. Homework Equations End products will be Vc(t) = i(s)R + (Vo - i(s)R)e^(-t/RC) and i(t) = (Is - (Vo/R))e^(-t/RC) The Attempt at a Solution Using KCL on a hypotetical RC circuit with a...
  33. 2

    Natural response and step response

    ok i need some clarification if you have a circuit where a current source is in parallel with an inductor a resistor and a capacitor is this considered a natural response or a step response. I guess i thought a step response is if a switch is switched and a source is added then it is a step...
  34. P

    Step Response of System with Pole in s = 0 at Infinity

    Homework Statement A contininous time system has when laplace transformed, a pole in s = 0. What is de stepresponse for the system when t goes to infinity Homework Equations H(s) is infinity in 0 (H(s) is unit response laplace transformed) s(t) = h(t) * u(t) (the stepresponse is the...
  35. Q

    Step Response of an LTI system

    Hi lads, need help with this question from a signals and systems course. LTI system is defined as follows H(s) = \frac{1}{ s^2 - 2rs cos(theta) + r^2} where r = 20pi, theta = 1.47. Find an expression for the step response of the system I think...
  36. 0

    Integration and RC Step response

    Integration Homework Statement Hi everyone, I'm new here. This is my first post. I found physicsforums when researching on google a solution for a doubt I've had when trying to solve rc step response. Basically, the RC analyse showed at...
  37. V

    Step response of a first order system

    Homework Statement Find the unit step response of the transfer function... a) G(s)\,=\,\frac{4}{s\,+\,4} b) G(s)\,=\,\frac{2}{0.2s\,+\,1} Homework Equations General first order step response equation... C(s)\,=\,R(s)\,G(s)\,=\,\frac{a}{s(s\,+\,a)}, where R(s)\,=\,\frac{1}{s} then do an...
  38. A

    Engineering RLC circuit step response time domain

    This is more of a math question but i feel like i will get more help among Electrical Engineers. I successfully found the step response of an RC circuit in the time domain using Laplace Transforms. But i can't seem to figure out how to do it with an RLC transfer function. I have the following...
  39. F

    Unit Step Response: Solving s(t) = e^{-t}u(t) for u(t) - u(t-2)

    The step response of an LTI system is given by s(t) = e^{-t}u(t) . Find its response to the input u(t) - u(t-2) . Note: u(t) is the unit step function. So I have the solution, but I do not understand it. y(t) = s(t) - s(t-2) = e^{-t}u(t) - e^{-(t-2)}u(t-2) I really don't...
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