Not an "autotransformer"
You probably want to stay away from an "autotransformer" in this situation because of line isolation factors.
A simple "step down" of "step up transformer would be a safer choice, where there is a primary and
a secondary winding configuration.
Do your homework before delving into this transformer application.
Regards,
Roland F. Harriston, P.D.
***************************
From: "jim.strohm@... [Homebrew_PCBs]" <Homebrew_PCBs@yahoogroups.com>
To: "Homebrew PCBs" <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, February 24, 2016 9:29:25 AM
Subject: RE: [Homebrew_PCBs] Re: drill pcb
---In Homebrew_PCBs@yahoogroups.com, <keethpr@...> wrote :
To: "Homebrew PCBs" <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, February 24, 2016 9:29:25 AM
Subject: RE: [Homebrew_PCBs] Re: drill pcb
Depends. Most of them are autotransformers. In this case, the full winding is used for 220 and it's tapped halfway down for 110. I got my last two for free on CraigsList.
Aren’t most of these converters to convert 220 down to 120 ?
International voltage converters are widely available in the states.