----- Original Message -----
From: <gopi@sloth.org>
To: <brian.tiplady@astrazeneca.com>
Cc: <newtontalk@planetnewton.com>
Sent: Friday, June 09, 2000 7:39 PM
Subject: RE: NTLK Newt Adaptor
Thanks for everybody who replied.
I'll not use other adaptors at least until I'll
get one from Apple and test it carefully
with multimeter under load.
> > > So, be very careful. I would try to shell out $20-30 instead
> > > of having to return my MP to Apple and pay ~$200 for the repair...
>
> "...it likely to drop down to..." is not a good phrase to use when
> referring to expensive electronics gear. A couple important points. It
> _is_ putting out 15v. While it may drop quickly, do you want to test
> experimentally how long your newton can take 15v before it's unhappy?
> also, it's not like an (unregulated) adaptor will just sorta drop from 15v
> to 6v the moment you draw a microamp from it. The drop will depend on the
> amount of current being drawn by the device. I have verified this
> experimentally in the past...
Wrong. The time needed for voltage to change depends on Capacitance
and Resistance of the network (C*R). Note, that in case the input
capacitance
of Newton is larger than the output capacitance of the adaptor,
the voltage will NEVER be higher than that of a loaded adaptor.
> Another important aspect of this is that the Newton uses the
> voltage/current response characteristics of the power supply to regulate
> teh battery charging current. Too much current and the batteries will get
> very hot...
This is more serious issue. If you really mean that Newton does not have
any charging circuit, this is very important.
> Bottom line: If you want to use a non-Apple power supply, check out the
> interconnect port docs, and get a power supply that meets the same
> voltage/current response curves as the Newton expects. You'll probably
> have to design your own supply. And consider that if you are capable of
> doing that, you are probably capable of earning more than the cost of the
> power supply in the time it would take you to design one :)
Not a good joke. An example of false logic.
I am capable of designing almost any power supply.
Three years ago I've designed the portable cardiograph device
for use with Newton - that got the medal at exhibition in Bruxells.
But I am living not in USA... That makes your conclusion false.
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