# transfer function for passive filter

#### notoriusjt2

Joined Feb 4, 2010
209

the book gives me

Laplace impedance for a capacitor is Z=V/I=1/Cs

what is the Laplace impedance for an inductor? Z=Ls?

so would Vout=(Zc/R+Zc+ZL)Ein
(1/Cs)/(R+Ls+(1/Cs))
im getting

#### mik3

Joined Feb 4, 2008
4,843
The correct answers are d and e.

#### hgmjr

Joined Jan 28, 2005
9,029

the book gives me

Laplace impedance for a capacitor is Z=V/I=1/Cs

what is the Laplace impedance for an inductor? Z=Ls?

so would Vout=(Zc/R+Zc+ZL)Ein
(1/Cs)/(R+Ls+(1/Cs)) (This expression is correct)
im getting
You are so close.

hgmjr

#### hgmjr

Joined Jan 28, 2005
9,029
Mik3, Initially I thought as you did. On closer inspection I think you will find that answer e. does not equate to d.

hgmjr

#### mik3

Joined Feb 4, 2008
4,843
Mik3, Initially I thought as you did. On closer inspection I think you will find that answer e. does not equate to d.

hgmjr
Ohhh, yes you are right. The correct answer is d. The numerator of e should be 1/LC as for e to equal d.

#### hgmjr

Joined Jan 28, 2005
9,029
Yeah. Like I said, I initially drew the same erroneous conclusion but then looked closer and realized my ooppss.

hgmjr