I just used my "Kill-A-Watt" power meter to take a look at several wall
warts. All the samll ones were slightly warm to the touch, at no load
used less than 1 watt (limit of resolution) on the power meter, and had
a power factor down in the .15 range. I tried a bigger one used for
charging my big cordless drill, it ran 4 watts and .47 power factor.

As a side note, I got a "Kill-A-Watt" power meter
http://www.p3international.com/produ.../P4400-CE.html
run about $30 to $35, used it to track down about 3/4 of my total
household power useage. The wall warts were NOT an issue, the freezer,
the refrigerator, and my wife's reading lamp were heavy hitters. The
reading lamp got a 40 watt florescent, saves about $6 a MONTH on that
item alone!!

I took a reading for several days on each item, loaded the KWH reading
and hour reading into a speadsheet, and calculated the monthly power
consumption and cost. Real eye opener!

Siggy wrote:
A while back there was a discussion about why wall wart transformers that
were not under load would draw no current. Anyone recall that thread? As I
recall there were some references to the induced currents created by
collapsing magnetic fields etc.

Anyway, I'm trying to either prove or disprove the statement that unplugging
wall warts when not actually using them to power or re-charge your device
will save electricity. My recollection is that it doesn't matter. Right or
wrong?