what does '~' mean?

[The Fatty]

when it say for example refresh rate ~72Hz what does the ~ mean? surely not AC?

[Kramer]

No, in that context, definately not AC .

That symbol usually refers to a "complete oscillation".

[The Fatty]

so whats it mean when in context with my lcd projector?

[Kramer]

Sorry, just edited my reply as I thought is was a bit brief .

"complete oscillation" as in it will accept an input signal of 72Hz.

[The Fatty]

so is that gd then? ir is it bad?

[Craig_E]

I don't really know what it stands for in every context, but I do know it's called a tilde
http://en.wikipedia.org/wiki/Tilde

[MattB]

In an engineering context, tilde is often used as shorthand for 'approximately'.

[ZippyCat]

Originally Posted by MattB

In an engineering context, tilde is often used as shorthand for 'approximately'.

As MattB said, it means approximately.