Re: [NTLK] Generic AC adapter

From: Damien Batstone (djb_at_er.dtu.dk)
Date: Sat Nov 09 2002 - 05:33:09 EST


At 13:56 08-11-2002 -0600, you wrote:

>On Friday, November 8, 2002, at 01:41 AM, Johannes Wolf wrote:
>
> >
> > You can be really lucky that your Newt survived so far:
> >
> > 7.5V @ 700mA means (in case this is not a hitech REGULATED power
> > adaptor)
> > that the LOWEST voltage at 700mA max will be 7.5 V and if you load it
> > with
> > less than 700mA, the voltage will rise quickly.
> > Since the maximum nominal input voltage of the Newt is 7.5V this is
> > definitely a dangerous behaviour!
> > I have measured up to 12V out of such adaptors if unloaded...
> >
> > Of course the Newt is very robust and may survive some overvoltage,
> > but I
> > can tell you: after I have ripped my first MP2100 totally by accidently
> > applying 9V to it, I will never perform such experiments again!!!!
> > The very first thing I do is to take my little voltmeter and check the
> > output before I connect my Newt.
> >
> >
>
>Maybe I have been lucky, but that's rarely the case for me!
>FWIW, I put my Snap-On digital VOM across the plug of the adapter and
>got just under 9 VDC with only the load of the meter. All I know is that
>it seems to charge in a manner that I would expect. I haven't noticed
>the battery getting hot while the adapter is attached (and charging) and
>I'm using the Newt.
>John
>
>"Got Newt!"

Just hope that the fridge/washing machine/oven/hot water system doesn't
switch off while you are using it. Or all at once! Regulated power
supplies are very cheap now, and you can test them easily. I'm running
mine on a 4.5V regulated supply that I had sitting around. It actually
applies around 5V_at_0A, and the plug fits perfectly. Backlight hums at a
lower freq than with the 7V laboratory adapter though. Is that bad for it?

Cheers,

Damien

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