a/c phase and vector angles

[johnfin]

If I know the phase offset for a sine wave how do I calculate the vector angle?

 

[Sal]

Hi

your qustion doesn't have many details, therefore I am going to comment what I undertand from it.

I assume y = sin(x+q) where q is the known phase, x and q are assumed to be in radians, therefore you have already the angle in radians. If you want the angle in degrees, calculate

d = q*360/(2*pi)

if you think this info is helpful click on "helped me" for statistics

Sal

 

[johnfin]

The phase shift is a linear dimension in which the vector angle is calculated. That is what I need to know. If I have 2 sine waves on a scope, channel A and B, and I know the phase shift, I would like to know what the vector angle is.

Look at page 5 of **broken link removed**

 

[Sal]

Hi

Then, we are talking about the same thing. However the osciloscope has its time range wich should be take on account. If you have tha 2 sines as in the figure above the text "Phase shift between waves and vector phase angle" in your link, then my previous answer is valid. The phase is linear, that is right, from 0 to 2*pi, or equivalently from 0 to 360 degrees.

Sal

 

[johnfin]

Sal, say you have a sine wave that is 1" long , 360 degrees, start to finish, and another that starts 25% later, that would be a 90 degree vector angle, correct. If you agree, how can I plug those numbers into sin(x+q) to get 90degrees? Thanks

 

[Kral]

johnfin,
If you are expressing the 2nd vector using the first vector as a reference, then q = -90 (or pi/4, in radians). It's as simple as that!
Regards,
Kral