Editing Step response (section)

{{Short description|Time behavior of a system controlled by Heaviside step functions}}
{{redirect|step change}}
[[File:High accuracy settling time measurements figure 1.png|thumb|300px|A typical step response for a second order system, illustrating [[overshoot (signal)|overshoot]], followed by [[ringing (signal)|ringing]], all subsiding within a [[settling time]].]]
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 function]]s. 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 [[Dynamical system (definition)#General definition|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 theory|stability]] of such a system, and on its ability to reach one stationary state when starting from another.