Will this power adapter work with a Duo 230?

[Marc Sira]

> I've found a guy selling an Apple Powerbook 45w power adapter Model M3037
> (APS-76) DC out 24v 1.88a
> 
> He claims it will work with all Powerbooks raging from the 190 to 3400.
> Will it work with a Duo 230? It may sound silly after what he's said, but on
> my technical information sheet, it says the Duo uses an AC100-240v at 1.0A

It will do what he says. It'll also work on some more recent iBooks and
Powerbooks (the ones with that style of power jack).

> Will his 1.88a be too much for the 1.0a requirements of the Duo or am I just
> splitting hairs? I should mention at this point that I know nothing about
> currents and what is potentially damaging to the computer, so I would be
> glad of any advice to make sure :)

The way you can imagine it is that 1.0A is the minimum the computer requires
(or actually 24W, since it arrives at 24V DC). If the adaptor can supply a
maximum 1.88a (45W) then the computer's needs are met, so it's happy. The
adaptor can work at part capacity, so it's happy too.

In fact you can also do the reverse and use the 24W adaptors on computers that
arrived with a higher-wattage one, because few notebooks really require that
much to operate. Using an old 24W adaptor on a Duo or iBook works, for
instance, but the battery may charge more slowly (or even drain slowly if
demand is high). The power manager appears to be able to deal with a variety
of cases. A lower-wattage adaptor can get pretty warm if the demand is
consistently too high for it though (since it would be constantly working at
its peak, with the battery filling in the rest). Not something to rely on if
the imbalance is severe, but I did use a 24W adaptor to drive a 2300c for
years with no problems at all (in fact, the computer never drew more than
about 15W). It can depend on what you're doing, though - I wouldn't try
watching a DVD or long Divx movie on an iBook with a 24W adaptor, but it would
be perfectly serviceable to charge the battery while the computer was asleep.

Now if the voltage were too high (a hypothetical 36V or 45V adaptor in a 24V
device), you could blow up your computer in an entertaining fashion. Mad Dog
probably has some more notes about that.

-- 
Marc Sira		|	toh at victoria.tc.ca
If you can't play with words, what good are they?