What is the meaning of phase difference?

[dervast]

Hi i have read that one signal is polarized when the phase remains the same (the phase difference is always the same) But what is the phase difference?

 

[FredGarvin]

In what context are you referring? The phase differernce of a periodic function is simply the time difference between corresponding points of two different functions. For example, three phase electrical. The phase difference is 120°. In vibrations, there are phase differences as well.

Take a look here: http://www.du.edu/~jcalvert/tech/threeph.htm
and here: http://cipco.apogee.net/foe/frwt.asp