On Wed, 8 Mar 2017 11:01:06 -0500, Ralph Mowery
wrote:


Many computers and some other devices have a switch for 120 or 240 volts
and that universal socket on the device. The suplies are really not
even that particular about the voltages, just get into the ball park
with them. Going 20 or 30 volts either way is fine.



These days the switchers are very wide mouth and can take anything
from 100-250v at any frequency, even DC although they are not labeled
that way. The first thing that happens is the input is converted to DC
immediately anyway. Then it is chopped to something in the 10s of
thousands of hz, fed through a small toroid transformer, regulated,
rectified and comes out at the desired voltage. When went to New
Zealand, all I needed was a plug adapter to run every electronic
device I had (laptop, phone, camera, MP3 player, tablet etc) All of
the chargers were 100-250v.