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Re: seeking apple IIc brick at 220V

sicklittlemonkey wrote:

Many appliances and most modern power supplies are rated
for 50Hz or 60Hz, so two types are not required.



Of course - modern ones. But I'm wondering about the Apple II
ones from 20+ years ago. Were the US supplies ok in Japan?


No problem.  The Apple was one of the first personal computers
with a *modern* switching power supply.  If the voltage is close,
the frequency is not a problem.

Switching power supplies just full- or half-wave rectify the
line voltage and filter it crudely with a large capacitor.  This
line-level DC voltage is then used to power the switch mode supply.

As a result, they are very tolerant of power frequency and waveform
variations.  As long as the capacitive filter has sufficient
capacitance to sustain the primary supply voltage between cycles
(or half cycles, if full-wave) of the line voltage AC, the supply
can maintain regulation at the output.

So, if the capacitance drops due to aging (drying out) capacitors
or the line frequency drops too low (usually by a factor of two or
more), then the supply may cease to regulate.


I remember reading a few years back about Japan considering
the switch to 200V+ for the efficiencies. Pipe dreams, really.


Yes, I used to use the consumer AC standard as an example of a
very high inertia standard.  I proposed that it would take *more*
than an act of Congress to change it, since they would all be
voted out of office if they attempted it.  ;-)

-michael

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

"The wastebasket is our most important design
tool--and it is seriously underused."