NTLK Reversed polarity for ac adaptors

From: Gruendel, Frank 3837 PPE-WT (Frank.Gruendel@de.heidelberg.com)
Date: Tue Jun 13 2000 - 08:53:00 CDT

Howard Moftich wrote ages ago...

> I have a universal adaptor powerful enough
> to feed Newt, so I'd like to connect it.
> Also - maybe somebody knows what
> happens if the polarity is reversed ?

Someone answered...

>Newton death. Have the number of Apple service ready.

I've never tried this with an ac adaptor and I don't intend
to, but I'd be willing to bet that nothing at all would happen.
After all, reversing the ac adaptor's polarity is pretty much
the same as inserting all four batteries backwards, and if this would
kill a Newton, there'd be heaps of dead Newtons out there (and
at least two in my drawer...).

However, make sure the voltage doesn't exceed 7.5 volts. Don't
try to reason or argue that it'll drop as soon as the Newton draws
current. It will, but you can't know how fast and how much.
I'm using a (nearly) unregulated power supply with one of my Newtons,
but I only dared this after verifying that a) the voltage when not
connected is less than 7.5 volts (a multimeter will do for that)
and b) there are no short voltage spikes due to inferior internal
regulator electronics (you'll need an oscilloscope for that).

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