equation numbering in an appendix

[E. Kaplan]

I am using an article document class, and have equations in the body of 
the article and in the appendix.  I would like the equations to be 
numbered sequentially, and the numbering restarted in the appendix and 
appear as: A1, A2, etc.
How do I do that?  I tried the various suggestions on the archive, but 
none worked.  I do not really want to number all the equations by 
section, as provided in 1.6.5 by the new modules (that got the appendix 
equations to appear as .1, .2 etc.).

Thanks,
EK