The terms

**or***Steady State***is defined not only for electrical systems, but for many other physical systems also.***Transient State*
The transient response does
not depend on the source i.e. forcing function, applied.

**. Mostly transient response is associated to on/off events. Previously the circuit is switched off. Now it is suddenly switched on and switched off (impulse). What is its response i.e. output?***It is purely natural response*
OR

Previously the circuit is
switched off. Now it is suddenly switched on and kept on. What is the response
i.e. output?

These types of responses are
usually considered as transient responses.

*In general transient response refers to the response due to change in equilibrium states.*

Steady State occurs after
the system becomes settled and at the Steady State system works normally. It depends
on the forcing function i.e. source

Now, we will take a physical
example to understand the difference between the two states.

Suppose we throw a stone
into a stagnant lake. Before we throw stone, the lake is in equilibrium. When we
throw the stone, the stone collides with the surface of water. Thus the
momentum of stone is transferred to water. Water produces ripples. Ripples die
out after some time and the stone sinks and the water is back to its stagnant
state.

Observations:

- Stone collides with the surface of water, forcing function which exists only for a certain small time. Like an impulse.

- Water produces ripples are the transient response.

- Ripples die out after some time and the water is back to its stagnant state is Steady State response.

Now we will go into the
discussion back while taking an example of Electrical circuit. Consider the
circuit given below.

**If the battery is ON at t=0 and kept ON.**

Inductor has no energy
stored initially. So it has no voltage across it.

Inductor voltage = 0

Rate of change of current =
0

Initially current in
inductor = 0

Energy stored in inductor =
0

As we know that Inductor
does not allow sudden change in currents. So just after the moment when switch
is ON, the current in inductor is zero. That means at t=0+ inductor acts as
open circuit. But as the time passes inductor allows current. This happens
until coil voltage drop is equal to applied voltage.

But after some time, i.e.
when coil voltage drop is equal to applied voltage, then current flowing
through the circuit is constant as inductor voltage is zero which means rate of
change of current is zero. This state is called Steady State.

So if we solve the differential equation of the circuit,
we’re actually finding the response as a function of time, which includes both
transient and steady state response.

**Thank you!**

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