# Phase question

1. Sep 11, 2007

### nicktacik

1. The problem statement, all variables and given/known data
If I have a transfer function $$H(jw)= |\frac{V_o}{V_i}|$$. I need to find the phase difference between Vo and Vi.

2. Relevant equations

3. The attempt at a solution
The phase angle is $$tan^{-1}(\frac{Im(H)}{Re(H)})$$. My problem is that if I get a positive angle, does this mean that the Output leads or lags the input? I can't find this explained clearly in any text.

2. Sep 11, 2007

### learningphysics

A positive phase difference is a lead. A negative phase difference is a lag.

3. Sep 11, 2007