Question

igure 5 Low Poss Filer Cecuitf

THE TIME CONSTANT IS RC FOR THE ABOVE CIRCUIT.

7. If we have a fast-moving input signal that we want the output to follow, would we want to have a time constant that is small or large?

8. If we have a slow-moving input signal that we want the output to follow, but a fast-moving noise on the input that we want to filter out, would we want to have a time constant that is small or large?

9. What does it mean if the dynamic system you are studying has a steady state gain greater than 1?

Answer 1

This is totally a Qualitative Question.Conceptual one.So i will answer accordingly.

First of All we must understand what is the meaning of Time cknstant becuase this is the essence of the first two questions.

Time constant of any circuit signifies that in how much time the output of the system will be 63.2% of the final value,assymptotic final valye.If it is the case of discharging then the time taken to reach 36.8% of the initial value.

So it basically tells us how fast or slow the system response is.

Now in Question 7.We want to 'track' a fast moving input.So response must be fast.So time constant should be less,or lower, because lower time constant means system reaches its final value quickly.

In the second Question we have a slow moving input and a fast moving input noise..The output must follow input and should not follow the noise.We have to make the time constant large.So that system doesn't respond to The noise,but responds to the slow movinh input.

In question 9 if the steady state gain is greater than 1 then this means that ouput will be greater than the input in steady state.Basically means that the ouput will be amplified.

Hope this helps