Re: [NTLK] After-market power adapter

From: Johannes Wolf (mp2100_at_mail-gw.estec.esa.int)
Date: Wed Jun 16 2004 - 06:25:04 PDT


Does the multimeter not support current measurements?
If it has a 10A range (which is quiet common for multimeters) you put the
multimeter into that mode and just shortcut the adapter with the two
multimeter leads having the meter inbetween.
Then you should get a current reading.

But as long as you do not intend to charge rechargeables inside the Newt it
does not really matter.

So at the end I think it was worth the effort to check the output voltage
rather than frighing the Newt first. It seems that the seller was right
stating that the label on the adapter was not the correct one.

BTW: I prefer using the built in battery monitor of Avis Backdrop.
This utility also shows the actual current drawn from the Newt itself.
In case you get a reading for the charging current only, you will not see a
significant value until you put in the rechargeable Battery pack.
With Avis BD you can see the difference between BL on/off very well. This
difference should be in the range of 30 ... 50 mA. And more interesting you
can actually see the current consumption of your cards that you intend to
plug in.

Cheers
Johannes

> -----Original Message-----
> From: newtontalk-bounce_at_newtontalk.net
> [mailto:newtontalk-bounce_at_newtontalk.net]On Behalf Of
> dlandown_at_chroma.med.miami.edu
> Sent: Wednesday, June 16, 2004 2:47 PM
> To: newtontalk_at_newtontalk.net
> Subject: Re: [NTLK] After-market power adapter

> Thanks. With this encourgement I borrowed a multimeter. It read 7.5V but
> I couldn't get a current reading. The label on the adapter says
> switching power supply, I thought that might be why I couldn't read any
> current.

> I'm running on the Newton on 4 AA batteries. I opened the SBM utility -
> Battery indicator and then plugged in the adapter

> no adapter just plugged in 15 min later

> Voltage 4.975 5.210 5.259
> %Capacity 39 63 67
> AC applied no yes yes
> charge state discharging discharging discharging
> charge current unknown 2.415 mA 2.415 mA

> and no new smell from the Newton :)

> Turning on the backlight didn't change the numbers. The charging current
> bounces between 1.9, 2.4 and 2.8 mA which must be a lsb issue.

> I wanted this adapter to run the Newton while plugged in, mostly to
> support cards. I think it will work for that. This is not a complete
> endorsement, I haven't tried to charge the rechargable batteries (I don't
> have any).

> David
SNIP

-- 
This is the NewtonTalk list - http://www.newtontalk.net/ for all inquiries
Official Newton FAQ: http://www.chuma.org/newton/faq/
WikiWikiNewt for all kinds of articles: http://tools.unna.org/wikiwikinewt/


This archive was generated by hypermail 2.1.5 : Wed Jun 16 2004 - 07:00:01 PDT