Re: seeking apple IIc brick at 220V

["Michael J. Mahon" <mjmahon@aol.com>]

Robert C. wrote:
> "Linards Ticmanis" <ticmanis@gmx.de> wrote in message 
> news:439b0ce4$0$27884$9b4e6d93@newsread4.arcor-online.net...
>
> > Robert C. wrote:
> >
> >
> > > I think Earth is right, if I am not mistaken it is only North America 
> > > that uses 110/120 Volts, Every one else uses 220 Volt Mains.
> >
> > Some parts of Asia and South and Central America have 110 Volts too I 
> > believe. Japan has 100 Volts I believe. Europe is now on 230V, as a 
> > compromise between the old British 240V and the continental 220V.
> >
> > --
> > Linards Ticmanis
>
>
> Just another way of confusing everyone, especially those who must design 
> international power supplies. I've often wondered how it's done; I only know 
> how to build simple "transformer-rectifier-regulator" type supples. 
> Switching supplies like those used on the Apple or PC's are beyond my 
> knowledge. (But if anyone knows of a good website that explains switching 
> supplies, I'd be willing to learn.)

Here's a start:  http://www.onsemi.com/pub/Collateral/SMPSRM-D.PDF
Google offers many more...  ("switching power supply" tutorial)

The basic idea of a "universal" supply is to build a switch mode
power supply that is able to supply the load on the miminum input
voltage, and has a mains-side bridge and filter that is safe for
the maximum input voltage.  Then it's just a matter of letting
the switch mode supply do its load-side regulation.

BTW, you consider 115v a problem.  I consider 50Hz a problem--
I can see 50Hz flicker quite distinctly!  (At 60Hz, it is barely
perceptible to me.)

But what I *really* don't get is the humongous plugs so popular
in the 220v world!  At 220v, you have the potential (!) to reduce
the size of the current-carrying conductors, and the insulation
for 220v is insignificantly different than for 115v, but all that
is squandered with gigantic plugs (and sockets).  ;-)

-michael

Music synthesis for 8-bit Apple II's!
Home page:  http://members.aol.com/MJMahon/

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