# Can't see the error in the transfer function

• STEMucator
In summary, the conversation is about a student's confusion with a problem involving transfer functions and bode plots. They mention deriving the transfer function and filling in a table, but are having trouble with the phase plot. After some edits and calculations, the student realizes their mistake and the problem is resolved.

Homework Helper

## Homework Statement

Here is the problem:

## The Attempt at a Solution

Okay so I was REALLY confused as to why something wrong happened. Here is my work for the whole question:

Sorry for the terrible writing.

Okay so for part a), I derived the transfer function as required. I had to be careful about the impedance of the capacitor though. Then I went to fill in the table and I got the results displayed above.

It appears the bode plot information in part a) is correct by looking at part b), which indicates a high-pass.

What doesn't make any sense though is the phase plot. The phase characteristics I found in part b) are clearly correct, but do not match up to part a) at all.

I have been staring at this for an hour now and I can't see what's going wrong. Could someone shed some light on this?

Thank you.

EDIT: Please note for part a), I computed the phase ##\Delta \phi## by using:

##\Delta \phi = - \text{arctan}(\frac{\omega}{\frac{10^6}{1.2}})##

EDIT2: Wait wait I think I figured it out, I forgot about the ##90^o## angle for part a), so that would mean:

##\Delta \phi = 90^o - \text{arctan}(\frac{\omega}{\frac{10^6}{1.2}})##

EDIT3:

Never mind guys, everything appears to make sense now that I fixed the phase characteristic.

Thank you anyway.

Last edited:
Zondrina said:
Never mind guys, everything appears to make sense now that I fixed the phase characteristic.

Thank you anyway.
No worries! It's always satisfying to sort out a problem yourself.