[vdr] Re: Power consumption of Hauppauge cards

["Reinhard Walter Buchner" <rw.buchner@freenet.de>]

Hi Stefaan,

> Power dissipation:
> 
> 1) System off, so ATC PSU is stand by  : 3W
> 2) System started, without Hauppauge card : 35W
> 3) System started, hauppauge installed and tuned on any sat station :
> 47W
> 
> Peak value during channel start : 50W (only for a short time)

I would question the reliabilty of such a measurement. What
percentage of error does your wattmeter give (dependent on
amperage)? The device (electronically) does nothing more than
multiply V * A and may take cos phi into account. The problem
is the following:

At 220V the difference of 47W-35W = 12W ==> 54mA @220V
At 12V this is already 1A difference at 5V it would be over 2A
and at 3.3V it would relate to ~ 4A difference. No one knows
how this difference is distributed over the supply voltages.

Plus I seriously have my doubts about 50W being the *true*
instantainious wattage. All wattmeters have some kind of
time base.

Greetz,
Reinhard


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