Hi!

I'm currently taking a class called AC Principles and have a few questions. Our instructor has been teaching us about sign waves and I'm having a hard time understanding peak voltage.

How do we know that the peak voltage of a 120VAC sign wave comes to 170 volts?

And how does the figure ".707" relate to the 170 volts?

We'll be getting into 3-phase in the next class and I don't think I have grasped this concept yet.

Thanks!