Re: [NTLK] Solar Powered Newton

From: Marco Mailand (
Date: Tue Mar 05 2002 - 02:52:43 EST

> Though, the Newton itself will regulate the power, perhaps something
> simple like a series diode+diode clamp+capacitor would do.
A regulation is in principle not necessary since the Newton will use the
extra power at bright sunlight to charge quicker. I'm afraid of killing the
internal security circuitry by overvoltage and strong current. Apple used a
Z-diode to protect the regulator, but it can do this only for a while. If
you e.g. connect a 12V source to the Newton which is capable of delivering
1A or even more the Z-diode will be thermally blown after a few minutes and
the overvoltage will then kill the motherboard. I know this seriously from

However, most solar panel might be not capable of delivering 12V and 1A, at
least not those which have the size of the Newton, there is a similar habit
of use: left unattended in bright sunlight over several hours. I also found
that some solar panels are rated for e.g. 6V but will deliver 9V under
bright sunlight, but with no load. Any means to dispose surplus energy
outside the Newton is thus more then appropriate and I think a well
dimensioned Z-diode (e.g. 7.1V) is just good.

With best Regards / Viele Gruesse!

Marco Mailand

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