Homebrew PCBs

I have been ignoring the back and forth arguing but here is an undiscussed warning:

 

That a VARIABLE auto-transformer (Variac) works stepping down 220V to 110V does not mean that it can be wired backwards and step up 110V to 220V.  

If it is turned down, the output voltage will get higher and higher and it will eventually short the 110V input line.  Lots of fireworks and destroyed equipment.  

This does not apply to fixed ratio auto-transformers.

Bertho