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From: "Phil Allison"
References: <email@example.com> <firstname.lastname@example.org>
Subject: Re: Doubling wallwart power rating
X-Newsreader: Microsoft Outlook Express 5.50.4522.1200
Date: Tue, 8 Oct 2002 00:28:56 +1000
NNTP-Posting-Date: Tue, 08 Oct 2002 00:16:52 EST
Organization: Telstra BigPond Internet Services (http://www.bigpond.com)
"John Woodgate" wrote in message
> Someone in this thread said that there is a compensation effect - less
> induction implies less magnetizing current. So, over a range of output
> currents, the input current magnitude may be nearly constant (but the
> phase varies). Except for a very small transformer indeed, (e.g. 1 VA),
> the magnetizing current is much less than the total input current at
> rated load, so the constant-current range is likely to occur under some
> rather light load conditions.
** John is speaking off the top of his head again. How many wall
warts has he measured I wonder - less than me for sure.
The last one I saw was rated at 12 volts and 500mA DC. It drew
the same primary rms current with both full load and no load.
You have to do tests to know - theory will not tell you.
. . .. . . .. love Phil
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