From: Lizard Blizzard
Subject: Re: Complete newbie - about voltage regulator
Date: Mon, 13 Jan 2003 08:06:29 -0800
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Zalek Bloom wrote:
> I built an external battery pack for my PDA. My PDA has built-in 1000
> mAh battery, and I built an external battery pack composed from 4 AA
> 1.2V, 1800mAh batteries - so I have exactly 5V.
No, you have 5.7V fully charged, and 4V fully discharged. That has been
what I've measured with Ni-MH cells.
> I am thinking about
> using sometimes 4 regular AA alkaline batteries, but a regular
> alkaline battery has 1.5V, so my pack will have 6V.
No, again you will have about 6.5V with fresh batteries, and something
in the 4 to 4.4V range when fully discharged.
> Can you give me a name/type of a simple voltage regulator that has an
> input of 5 -12 Volt and an output of exactly 5V?
You should use a DC to DC converter that accepts a wide range of battery
voltages and puts out a fixed voltage. Check out the battery power
management ICs such as the ones here:
But remember that your portable device probably has this kind of chip
already. So it may not be necessary.
----------------(from OED Mini-Dictionary)-----------------
PUNCTUATION - Apostrophe
Incorrect uses: (i) the apostrophe must not be used with a plural
where there is no possessive sense, as in ~tea's are served here~;
(ii) there is no such word as ~her's, our's, their's, your's~.
Confusions: it's = it is or it has (not 'belonging to it'); correct
uses are ~it's here~ (= it is here); ~it's gone~ (= it has gone);
but ~the dog wagged its tail~ (no apostrophe).
----------------(For the Apostrophe challenged)----------------
From a fully deputized officer of the Apostrophe Police!