Subject:
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Re: AC Adapter Specs?
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Newsgroups:
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lugnet.robotics
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Date:
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Mon, 25 Jan 1999 16:08:38 GMT
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Original-From:
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rajackson@+NoSpam+qnx.com
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Viewed:
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984 times
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Previously, you (Jim Thomson) wrote:
> > I would think 800 mAmps should be enough, but you can never have too
> > large a current-rating.
> >
> > Jasper
> > --
>
> I don't want to tread on anyones toes, but.......
>
> I agree that the current rating cannot be too large for a regulated supply,
> but for an unregulated supply this is not the case. The Maplin catalogue
> has this to say about an Unregulated 800mA power supply:
>
> "The unit is not stabilised and therefore at low current drains, the voltage
> can approach double the full load voltage"
>
> Jaspers suggestion of 800mA may well be fine, but I'd be very cautious about
> connecting my RCX (or anything else) to an unregulated supply with a large
> current rating.
>
> Apologies if this only confuses matters, but I thought I'd better add a word
> of caution.
For this type of application this is ok. All simple power supplies are basicly
peak detectors, under no load the internal resistance of the bridge and transformer
winding do not drop the voltage supplied to the filter capcitor. For this reason
the capacitor is usually spec'd to be twice the rated voltage (or greater). The
regulator (in the RCX) should be fine under these conditions since under no-load
it is not dissapating any heat.
>
> Jim
>
> --
> Did you check the web site first?: http://www.crynwr.com/lego-robotics
--
Did you check the web site first?: http://www.crynwr.com/lego-robotics
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