Order By and Comparisson

Hi,

just as I thought I had postgres mastered :)  the ordering of strings is
causing me some confusion.

Can someone explain how the database orders strings in the ORDER BY command.

My example:

My database is encoding is UTF-8, and default language is english,

If I have a text column in a table with the following rows:

'a'
'A'
'~'

Then in UTF-8, I would expect the order to give me

'A'
'a'
'~'

But instead I get:

'~'
'a'
'A'

Is there anywhere in the documentation I can get a more detailed
explanation of this?

Thanks.