What is Step Response?

LvW

Joined Jun 13, 2013
1,752
The time it takes for a device from off to on, or 0 to 1, depends what the context is.
Max.
I rather think, this is the rise time of a system.
The step respose is the timely response of a system output to a signal step at the input.
Example: The step response of a simple RC-lowpass is an exponential function-
 

bogosort

Joined Sep 24, 2011
696
Isn't that the same thing??:confused:
Max.
Rise time is a single figure of merit, whereas the step response encompasses the entire behavior of a system to a step input. When I hear the words "step response", I think of a time-domain graph of the output, which will show the rise time as well as the other figures of merit (overshoot, ripple, etc.).
 

danadak

Joined Mar 10, 2018
4,057
Think of inertia and resistance.

If I place a 100 lb weight on a friction-less table, it still takes a lot
of push to get the mass going. Thats inertia. Once I get it up to
speed, if its in friction-less environment it keeps going.

Now if I put it on a table with a lot of R-esistance its even harder and has to be
constantly overcome with energy expenditure, I have to keep pushing. So in-
tially I overcome the inertia but still have to keep pushing due to R.

So L & C represent components that exhibit inertia. The C does not want its
V to change (easily) and the L its current to change (easily). And the R converts
some of the energy I put into the system and converts it to heat, so some of
the energy input to system does its job, and some is wasted.

So when we apply a step V or I to a system it wants to take its own sweet time
to change, all affected by inertia and resistance. Even the L & C are not ideal
and have some R as well.


Regards, Dana.
 
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LvW

Joined Jun 13, 2013
1,752
Isn't that the same thing??:confused:
Max.
The rise time is one single number (time in seconds) which is derived from the step response which is a function of time.
The rise time gives you the time needed to reach the final value for the step response (within a certain error range, for example 1%)
 
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