wrote in message ...
Is there any cheap/easy way to measure the power consumption of mains
powered equipment that consumes a few tens of watts and is almst
certainly non-sinusoidal? In particular I want to measure the power
consumption of a (hopefully) low power PC that should be consuming
around 25 watts.

A cheap plug-in power meter (a Brennendal one) claims it's consuming
about 50 watts but I'm not at all convinced it's telling me the truth.

http://www.maplin.co.uk/Search.aspx?...eter&source=15


I know 'proper' power meters are expensive and I don't really want to
spend lots of money, nor do I really want a very accurate answer. If
I can just confirm it's consuming something between 20 and 30 watts
I'll be happy.

I'm not sure how it calculates things but current and voltage are usually
out of phase with computer power supplies so there's a few different reading
that can be taken.
The power in watts or kwh (over time) then there's the VA which is amps
X volts which gives you power but this might not be the same as watts.

I just tried one of our small Dell PCs in the lab, when it's off but plugged
in it's 10 watts and 125Watts when on, excluding monitor.

I find it hard to believe that a PC is 25-30w when on.
My 24" iMac is about 110w changing the LCD screen from minium to
maxium xhanged the power usage by nearly 20 watts.
Doenloadign a file added 5watts as I guess ther HD was being accessed.



Can one buy kwh meters relatively cheaply? I'm quite happy to wire
one up to a plug and socket and use that over several hours to see
what's being consumed.

--
Chris Green