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Finding the time constant

  • Thread starter Rombus
  • Start date
  • #1
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Homework Statement


Find the time constant
[itex] x(t)=4 e^{-4t} u(t)[/itex]

Homework Equations


[itex] \tau = \frac{1}{\lambda} [/itex]


The Attempt at a Solution


[itex] \tau = \frac{1}{\lambda}= \frac{1}{4} = .25 [/itex]

I know the unit step is shifting the start of the decay function to zero, but I'm not sure how or if this can affect the time constant. So my question is how does the unit step affect the time constant?
 

Answers and Replies

  • #2
Ray Vickson
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Homework Statement


Find the time constant
[itex] x(t)=4 e^{-4t} u(t)[/itex]

Homework Equations


[itex] \tau = \frac{1}{\lambda} [/itex]


The Attempt at a Solution


[itex] \tau = \frac{1}{\lambda}= \frac{1}{4} = .25 [/itex]

I know the unit step is shifting the start of the decay function to zero, but I'm not sure how or if this can affect the time constant. So my question is how does the unit step affect the time constant?
It has no effect. Just recall the definition of time constant.

RGV
 
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